WASHINGTON — The crowd booed Thursday afternoon as Jorge Alfaro left his perch behind home to plate to trot to the mound and throw his arm around Aaron Nola for a meeting.

This — a two-out, eighth-inning showdown with Bryce Harper — was the moment that would define a 2-0 win over the Nationals and perhaps set the tone for the rest of the season. A loss Thursday would have continued the Phillies' spiral, while a win would send them to Toronto with hope. The Phillies could handle a few jeers as Alfaro and Nola fine-tuned a game plan.

Nola's signature curveball was starting to lose shape, which prompted him to call for a chat with Alfaro after throwing three straight curves and falling behind to Harper, 2-1. Nola had pitched brilliantly all afternoon, but at last he was finally facing real trouble. Runners were on first and second. Nola had thrown 100 pitches. This felt like the ballgame. And a conversation on the mound would decide the game's fate.

"We talked about the pitch we should throw in that situation," Alfaro said. "We wanted to attack with that pitch and see what his swing is going to look like and then we go from there."

The pair opted to ditch Nola's curveball, which had fooled Harper earlier in the game. But there is only so much fooling you can do against one of baseball's premier hitters. This is a game of adjustments, manager Gabe Kapler said afterward. He called Nola a "creative genius" for his ability to recognize that his curveball was lacking and to alter his plan. Alfaro told his pitcher to not be predictable. So Nola scrapped his curveball and attacked Harper with a 94.5 mph fastball. Harper missed for strike two. And then Nola geared up another. He struck out Harper swinging at a 94.7 mph fastball to win the battle, strand two runners, and move the Phillies three outs closer to a pivotal win.

It was the fastest pitch Nola threw all afternoon and it was the final of 102 he would throw. Nola saved his best for last.

"I think it was the moment," Nola said when asked how he was able to amplify his fastball at the end. "I didn't want those runs to score. I tried to bear down as much as I could."

Kapler said Thursday afternoon that he believes Nola should win the Cy Young Award. But Nola will likely finish behind Washington's Max Scherzer, the pitcher he outdueled Thursday. And that is fine. The Phillies don't need him to be a Cy Young winner. They need him to be the pitcher they can turn to after losing four straight games and when it feels as if everything they built over the last five months is going to fade away. That's who Nola was Thursday. He struck out nine, walked just one, and allowed five hits in eight innings. The Phillies have won each of Nola's last four starts. They are 3-10 in their other 13 games over that span. The Phillies remain in the playoff hunt because of Nola.

"Right when we needed him most, right when we needed him to step up, he really just put the team on his shoulders and carried us today," Kapler said. "He gave us the opportunity to not make a whole lot of decisions, which was quite a nice break. But more than anything else, he was as we expected him to be against a former Cy Young Award winner and just dominated. It was an impressive performance."

Nola returned to the dugout after striking out Harper and Kapler told the pitcher that he was done. Thursday seemed like it might be the first time Nola would reach the ninth inning in his career, but the eighth inning was too laborious. Nola said he "went all-out" to finish that inning. There was no argument for the ninth. Pat Neshek retired the three batters he faced and a win was sealed.

"Last night was a tough one," Neshek said of Wednesday's walk-off loss. "We had to get that one today. So I'm giving everything I've got to close that out there. That was kind of special, because it was him and Scherzer."

Odubel Herrera provided Nola with the run support he needed in the seventh inning when he bashed Scherzer's cutter into the second deck of the right-field stands following a walk to Maikel Franco. It was just the Phillies' second hit off Scherzer. The other was a single that bounced off the shortstop's glove. Scherzer pitched seven innings and was just as dominant as Nola, but the Phillies were able to crack him.

Kapler often talks about Nola's "heartbeat" and how calm the pitcher stays on the mound. Spencer Kieboom started the third inning with a double and moved to third on a sacrifice. Nola never wavered. He struck out Adam Eaton and retired Trea Turner on a lazy fly to center. Nola allowed a two-out double to Mark Reynolds in the seventh and then retired Wilmer Difo to end the threat. Nola faced trouble but never seemed to be in danger. And then when danger finally came, he escaped without trouble.