ST LOUIS – Gabe Kapler met Seranthony Dominguez at the mound on Thursday night, handed him the baseball, and made sure the reliever was aware of the situation.

Busch Stadium was buzzing. The Phillies were clinging desperately to a one-run lead. The Cardinals had runners on second and third with just one out in the seventh inning.

Dominguez, a major-leaguer for all of 10 days, said he never faced a situation like this. But the righthander did not flinch when Kapler handed him the ball. It was a cool moment, the Phillies manager said after Dominguez recorded two key outs to preserve a 6-2 win. Kapler returned to the dugout confident that the 23-year-old – the bullpen's youngest pitcher – was right for the job.

"He's so calm. He's so relaxed," Kapler said. "He never gets too high or too low."

Dominguez needed just eight pitches to silence the rally and push the Phillies six outs closer to their eighth win in their last 10 games. They are nine games over .500, a half-game out of first place, and two blown saves by Hector Neris away from riding a 10-game winning streak. They are on quite the run.

Thursday was Dominguez' fifth appearance since being promoted from triple A. He has yet to allow a hit or walk and has retired 14 of the 15 batters he faced. This was his biggest challenge. Kapler called for him with the Phillies up against the ropes. No sweat.

"When I'm on the mound in a situation like that, I don't think of anything," Dominguez said. "I just try to stay focused. I want to help the pitcher and help my team and just get everyone out. When I got on the mound, all I said to myself was just jump ahead in the count and good things will happen."

Kapler was sent to the mound after Vince Velasquez, who turned in another great start, "allowed" a double to Matt Carpenter. The hit seemed like a routine flyout to left field before confusion overcame  Rhys Hoskins and Odubel Herrera. Herrera raced over from center and appeared to call off Hoskins, who dropped to his knees at the last minute to get out of the way. The ball dropped, the Cardinals had runners on second and third, and a rally needed to be extinguished.

"It was just a miscommunication. He called it but then he felt Rhys' presence so he felt like Rhys was nearby," Kapler said. "He just got a little gun shy. I talked to him after the game and I said 'We're going to be a little more assertive on the communication and call, call, call until the very last second and then we're going to catch the baseball because we're the centerfielder.' It's one of those things that you keep talking about but it's behind us and I trust Odubel."

Velasquez did not allow a run in 61/3 innings as he struck out five and walked two. He allowed just five hits and dominated with his fastball, which touched 98 mph. He was excellent. The Phillies starters have an 1.16 ERA in their last 10 starts and have allowed one or zero runs in 11 of their 13 starts this month.

Velasquez has made an effort to slow himself down and find his rhythm as he channels his aggressiveness. Thursday night he commanded the mound with a patient presence. He has allowed four earned runs over his last 171/3 innings. Velasquez may have turned a corner.

"It's just about having a different mentality going into the game," Velasquez said. "I told you guys that last week I just felt like I was going into more of a comfort zone of mine and that's something you have to have and cherish and build on. A lot of obstacles get thrown at you and you have to learn how to adjust. That's the whole part of this game, making adjustments and it seems like things are turning around, but there's still room for improvement."

The Phillies scored three times in the eighth behind a two-run single from Aaron Altherr and an RBI double by Herrera, who reached base for the 43rd-straight game. That provided enough cushion to take the stress away from the two runs Yacksel Rios and Luis Garcia allowed in the bottom of the eighth. The Phillies got them back in the ninth on a two-run homer by Pedro Florimon, who homered for the first time since September 27, 2013.

The game felt much safer after Florimon's homer than it did when Dominguez came in from the bullpen. The Phillies do not have a closer and Kapler has shed his bullpen of roles. The manager instead uses his relivers where best sees fit on a particular night. Thursday's pivotal situation – runners on second and third with one out, a one-run lead, and a rocking stadium – called for Dominguez' combination of a 98-mph fastball and wipeout slider.

The righthander became a relief pitcher three months ago when he pitched for the first time at double A. Dominguez needed just 11 minor-league appearances this season before the Phillies saw enough to promote him. It was hard to tell how little experience he has. He forced a groundout and a flyout and walked to the dugout with a one-run lead protected and a ballpark silenced. He was the right pitcher for the job.

"He's been as advertised," Kapler said. "A big arm and very calm, very composed."