ARLINGTON, Texas — The Eagles overcame another slow start and walloped the Cowboys, 37-9, with a second-half blitz Sunday night at AT&T Stadium. Here's what we learned:

  1. The Eagles aren't a fluke, Part VII. With six games left in the season, the 9-1 Eagles hold a four-game lead in the NFC East over the 5-5 Cowboys. Dallas has one more head-to-head meeting against the Birds, but not until the season finale. At that point, the division and maybe even home-field advantage throughout the NFC playoffs will be in the Eagles' possession. It would take a quite a fall for either the Cowboys or the 4-6 Redskins (0-2 vs. Philly) to catch the Eagles. The 2-8 Giants were mathematically eliminated from divisional contention Sunday. Doug Pederson won't allow his team to look beyond the Bears game next week, but it's difficult to envision the Eagles failing to wrap up a playoff spot over the next several weeks. The Seahawks and Rams follow Chicago on the road, and those will be stringent tests, but the Eagles seem incapable of slipping up, and certainly not on successive Sundays. For the third time in their last four games, they were sluggish in the first half. The offense executed the scripted opening drive to near perfection, and the defense kept the damage to a minimum of three field goals, but the Eagles struggled before the break. Carson Wentz and the offense couldn't get anything going in the air on the final five drives of the first half. He completed just 2 of 12 passes for 9 yards over that span. Dave Fipp's special-teams units were shaky. The kickoff crew allowed a 61-yard return to open the game, kicker Jake Elliott missed a 34-yard field goal (although he was likely affected by a concussion), and a Donnie Jones punt from the Dallas 45 bounced into the end zone for a touchback and a 25-yard net. "It's indicative of a couple of weeks off, having a bye," Pederson said of his team's slow start. But the Eagles came out like gangbusters in the second half, even without Elliott, and put a country spanking on the Cowboys, who suffered their worst defeat in nine seasons at "Jerry World." The Eagles haven't slayed any giants over the last month, but they have won comfortably despite not bringing their "A" games vs. the Redskins, 49ers and Cowboys. When the Eagles were at their best, they posted 51 points on the Broncos. They still have plenty of business to take care of, but the Eagles are too talented, too well-coached, and too confident to collapse.
  1. The Eagles are resilient. Pederson's steady hand has helped carry his team past first-half obstacles. When the Eagles went to the visitors' locker room at AT&T, there was no need for a tongue lashing or a rousing speech. Pederson trusts his players and coaches to be professional, and that's how he has treated them. "The message was that we were OK. We were fine," Pederson said. "Let's just get to basics and no one panic." Seven straight wins will strengthen the collective resolve of a team, but the Eagles couldn't afford a setback against their closest competitors in the East. "We were positive," guard Stefen Wisniewski said. "No one's going to get our heads down. We know we got a lot of talent on this offense. It's one of the best offenses in the league. Even if someone slows us down for a little while, we're not going to panic." The Cowboys defense had an effective scheme to limit Wentz's potency with the pass, but Pederson's lopsided play-calling didn't help his quarterback. The run-pass ratio wasn't egregious, but after the Eagles ran as much as they passed on their opening drive, Pederson called five rushes to 15 passes. But he was balanced on the Eagles' first two drives of the third quarter – both of which produced touchdowns – with a run-pass ratio of 8 to 5. The run game wore down the Cowboys, and with the Eagles having four options at running back (more on that later), Dallas never adjusted.
  1. The Eagles are prepared. The Eagles suffered another in-game injury, but again compensated for the loss. When Elliott left with a concussion in the first quarter, the Eagles adjusted to Plan B, however extreme. Linebacker Kamu Grugier-Hill, the emergency kicker, handled kickoffs, and Pederson decided to forgo extra points and field goals. "I went into go for it on fourth down in field-goal-range situations," Pederson said, "and scoring drives were just sort of a no-brainer, go-for-it, two-point conversions." Grugier-Hill was more than adequate. On his four kickoffs, he averaged 62.8 yards – slightly less than Elliot's 63.5 before he left – and had one touchback. He didn't have Elliott's hang time, but his distance was impressive considering he only once attempted a kickoff before Sunday. I wrote about Grugier-Hill's memory-making performance for my newspaper column. The Eagles took advantage of Elliott's injury by calling on the offense for four two-point conversion tries. They were successful on three and would have had a fourth had Zach Ertz not fumbled the ball just shy of the goal line. Nevertheless, the Eagles have suffered countless in-game losses this season – Ronald Darby, Jaylen Watkins, Rodney McLeod, Darren Sproles, Jordan Hicks, Fletcher Cox, Jason Peters, and Elliott, to name the most prominent — and almost every time, the replacement has more than held his own. That's preparation. That's coaching. That's having depth.
  1. The run game is lethally diverse. The Eagles, after finding snaps for all five running backs two weeks ago against the Broncos, couldn't have possibly been as charitable for a second straight game, right? Well, no, they couldn't. Wendell Smallwood, as expected, was inactive. But the four who dressed all received offensive snaps and touches, and each had an impact. Kenjon Barner made the best of his two plays on the Eagles' opening drive, catching a toe-tapping, 22-yard pass and then bolting the remaining four yards for a touchdown. LeGarrette Blount saw the field the most – he played 30 of 64 snaps – and logged 57 yards on 13 tries (4.4 average). Corey Clement received the next highest number of plays (19) and rushed six times for 50 yards. And new guy Jay Ajayi, despite the expectation that he would play more than he did in his first Eagles game, had just 13 plays. But he picked up 91 yards on seven carries – including a 71-yard explosion – and caught one screen for 10 yards. "It's different," Ajayi said of the rotation. "It's definitely not what I'm used to, but at the same time it's exciting to see all of us make plays." Why mess with success? The Eagles are winning, and if Pederson can feed all his thoroughbreds, there's no reason to revert to a workhorse backfield. "We got a lot of good running backs and a lot of different run schemes," Wisniewski said. "We've got a lot of run plays. It's probably hard to prepare for all of them as a defense."
  1. The Eagles offensive line might be the best in the NFL, even without Jason Peters. I'll get to Peters' replacement in a moment, but the o-line as a whole has been consistent throughout the season. They've run-blocked as well as any group — even the Cowboys — and have kept Wentz mostly clean, especially against four-man rushes. The interior of the line, especially center Jason Kelce, has been the lynchpin in the ground game. Whether he's angling off inside tackles or pulling on linebackers, Kelce has opened countless holes. Guards Brandon Brooks and Wisniewski have been just as effective. In pass protection, right tackle Lane Johnson has stood out and strengthened his case for a Pro Bowl bid. He held Cowboys defensive end DeMarcus Lawrence sackless — just the latest elite edge rusher he's kept in check this season. As for Vaitai …
  1. Halapoulivaati Vaitai isn't missing a beat. Many outsiders clamored for Howie Roseman to deal for an offensive lineman before the trade deadline. Many predicted doom with Big V tasked with protecting Wentz's blindside. But the second-year tackle has been a rock on the left flank, especially after some minor blips when he was initially called upon in the third quarter of the Redskins game four weeks ago. Vaitai had his issues jumping in for Johnson at right tackle last year. But he had hardly played on that side in college at TCU. The Eagles moved him back to the left side at the start of off-season workouts, and while he would have to be ready to play both ends as the swing tackle, the switch has paid off. The Eagles can run the same tackle traps as they ran with Peters because Vaitai is athletic, and they have decreasingly enlisted tight ends and running backs to chip-block on his side as he has grown more comfortable.
  1. Ronald Darby will upgrade the secondary. I expected Eagles defensive coordinator Jim Schwartz to ease Darby back into action. I was wrong. Maybe Schwartz stuck with him for the entire game after he saw how well he performed in the first quarter, but if the plan was to ride Darby for most of the 63 snaps, kudos to the coaches. Darby didn't look like he had missed the last eight games or that he was returning from a dislocated ankle. He tackled well (dropping Dez Bryant on a short screen early in the game). He covered well (deflecting a corner fade to Bryant in the end zone a play later). He used his hands well (popping the ball out of Terrance Williams' grasp and to safety Rodney McLeod for an interception). And he used his eyes well (turning back on a deep Dak Prescott prayer and notching his first pick as an Eagle). The Eagles got solid efforts from their cornerbacks in Darby's absence. Jalen Mills held down the left side and stayed there on Sunday even though Darby opened the season on that side. Mills made several stops and breakups against the Cowboys. Patrick Robinson was relegated back to strictly slot duty, but he was as consistent as ever. And while rookie Rasul Douglas and Jaylen Watkins never saw the field, their performances over the previous weeks will not be forgotten and will make Schwartz only that more comfortable calling upon them if need be down the stretch. But Darby returned and there appeared to be little reason to hold him back.
  1. Derek Barnett is hitting his stride. The Eagles' defense played to the final whistle. They didn't want to allow the Cowboys to reach the end zone, and much of that is simply about pride. It's also about having swagger. Schwartz's boys are cocky and play with a chip. Malcolm Jenkins, Brandon Graham, Fletcher Cox, Nigel Bradham, Tim Jernigan, and Mills – they love to hit and aren't afraid to remind opponents that they'll keep coming. Jenkins set the early tone when he got in Prescott's face after the quarterback stiff-armed him out of bounds. But there's one more defensive player who can be added to that stew of swagger: rookie end Derek Barnett. He gets better with each passing week. He recorded the second two-sack game of his career – and second in the last four games – and had two other hits on Prescott. He helped force the Darby interception, and his sack forced the fourth-quarter Prescott fumble that Bradham returned for a touchdown. The Cowboys were without all-pro left tackle Tyron Smith and his replacement (Byron Bell) was a downgrade, but Barnett had no say over whom he would face.
  1. Alshon Jeffery is becoming more of Carson Wentz's go-to receiver. On a night when Ertz (two catches for eight yards) struggled to regain his first-half-of-the-season, before-a-hamstring-injury form, Wentz relied on Jeffery in big spots, and the receiver delivered. It's not as if Jeffery hadn't been targeted much through the first nine games. And it's not as if his numbers Sunday were mind-blowing – he caught 4 of 7 throws for 67 yards and a touchdown. But there was something about the way he went into traffic and came down with clutch catches – an 18-yard grab over the middle on third down on the Eagles' opening drive of the second half; a 10-yard reception on third and 2 in the fourth; and a gutsy 17-yard touchdown catch on fourth down later that drive – that reminded this spectator why the Eagles signed him in the first place. Wentz has spread the ball around all season. But there are going to be days when Ertz is the No. 1 guy, days when Jeffery will fill that role, and days when someone else might step up. The Eagles, however, need Jeffery to remain a threat on the outside — although he lined up more in the slot Sunday than he had all season. He's their best weapon out there.
  1. And some leftovers: The Eagles' top-ranked run defense allowed 112 yards on 27 carries (4.1 avg.). Alfred Morris busted a few runs. Tackling and gap responsibility were the main problems. But the Eagles have yet to allow a 100-yard rusher dating to last season. … Nelson Agholor had only one catch for -2 yards, but it was oh-so-close to being a highlight-reel touchdown. The receiver spun out of a tackle, it appeared, and danced his way through a few more defenders on the way to the end zone. But a review of the play showed that Agholor's knee had touched the ground.