But the teammates on the field with the demonstrative right-hander nicknamed "Mad Max" were the never-nervous Nationals.
Scherzer whiffed Cespedes to win the 11-pitch battle and cap another impressive double-digit strikeout performance Friday night, when the reigning National League Cy Young Award winner earned the victory as Washington cruised past the Mets 7-2 at Citi Field.
"You kind of just get behind him and ride him -- he's big in those moments, he's big in the big moment and he's done it his whole career," Nationals catcher Matt Wieters said.
The final battle of the night symbolized an outing in which Scherzer relied more on his grit than his pure stuff. Scherzer got off to a slow start by his standards Friday, when he struck out just one and gave up one hit and one walk while plunking two batters in the first three innings.
But Scherzer recorded nine of his final 15 outs via strikeout to reach 10 strikeouts for the fifth straight start.
"You saw in the third inning -- he started getting it going," Mets manager Terry Collins said. "Mechanics, pitching, location and started mowing us down."
Scherzer threw just 67 pitches between the third and seventh before the eventful eighth, which began with Jose Reyes breaking up the shutout bid by homering to right field. Curtis Granderson then flew out to the wall in right before Scherzer struck out Michael Conforto.
Scherzer got ahead of Cespedes 1-2 before New York's left fielder fouled off five of the next seven pitches in working the count full.
"The buzz was a buzz of nervousness," Nationals manager Dusty Baker said. "You wanted him to finish, but you didn't want him to throw all those pitches in order to get it done. (Pitching coach) Mike Maddux and I looked at who we were going to go with, because they have left-right-left-right and we could go through the bullpen trying to matchup."
Aware he was facing his final batter of the night, Scherzer dialed his fastball up to 96 mph while mixing in some mid-80s sliders against Cespedes, who has 144 homers since 2012.
"I love it -- I love competing against the best," Scherzer said. "He's really one of the great hitters in this league. He can do damage at any time. You make a mistake, he's going to put it in the seats."
Finally, on his 23rd pitch of the inning and his 118th and last pitch of the night, Scherzer got Cespedes to swing and miss at an 86 mph slider.
"I knew that's my last batter," Scherzer said. "Knew I was at the end of the rope. That's just, 'Everything here is everything I've got and let's compete.'"
Scherzer slapped his hand into his glove as he stalked off the mound.
"It's pretty comfortable when you have Max on the mound," Nationals third baseman Anthony Rendon said. "I think you could tell that Max was pushing himself. It was going to be his last batter. He's a bulldog out there."
Scherzer allowed four hits and two walks in improving to 4-1 in his last five starts, though giving up a run Friday actually raised his ERA in that span to 1.13. He has whiffed 58 and walked just seven during his double-digit strikeout streak.
"It's a cool accomplishment," Scherzer said. "That's not easy to do. You've got to be on your game every single game and your pitches have to be sharp every single time."
Wieters and Michael Taylor provided Scherzer all the support he'd need with back-to-back solo homers in the third. Rendon hit a two-run shot in the sixth for Washington, which added three runs in the ninth on back-to-back RBI singles by Bryce Harper and Ryan Zimmerman and a bases-loaded walk by Rendon.
Harper finished 3-for-5 while Rendon and Taylor each had two hits for the Nationals (41-26), who have won the first two games of the four-game series against the Mets to extend their National League East lead to 10 1/2 games.
Jay Bruce homered leading off the ninth for the Mets (30-36). Bruce and Reyes finished with two hits.
Left-hander Steven Matz (1-1) took the loss after allowing four runs on eight hits, including the three homers, and no walks while striking out four over seven innings.
"When you're facing a guy like Scherzer, one of the best pitchers in the game right now, those mistakes are going to hurt you," Matz said.
NOTES: The Mets placed CF Juan Lagares (broken left thumb) and RHP Matt Harvey (right shoulder) on the 10-day disabled list and recalled OF Brandon Nimmo and IF Matt Reynolds. ... Mets IF Jose Reyes' eighth-inning homer snapped a homer drought of 129 at-bats dating to May 1. ... The Nationals signed RHP Edwin Jackson to a minor league contract and assigned him to Triple-A Syracuse. ... Nationals LHP Sammy Solis (left elbow) gave up one run in one inning for Triple-A Syracuse in his first rehab appearance Thursday.