Turns out, only his Philadelphia teammates' batting performance could keep Hamels from his 11th complete game.
The left-hander gave up five hits over eight innings in the Phillies' 9-3 victory Sunday night.
He batted to lead off the ninth, then the Phillies batted around, scoring six runs, and Hamels was lifted for pinch-hitter John Mayberry when his spot came up the second time in the inning.
"When you start games and you're pitching well you want to finish them," Hamels said. "But there's a window of time you have before you lose all ounce of strength and you get the stiffening up, and that's kind of what was happening."
Hunter Pence hit a pair of two-run homers to help the Phillies snap a seven-game losing streak against Washington dating to last year and avoid a sweep in the three-game series.
Of more concern to Washington will be the status of right fielder Jayson Werth, who left after breaking his left wrist while attempting a sliding catch.
"It's a clean break," Nationals manager Davey Johnson said. "He's going to be out for a while."
Washington rookie Bryce Harper stole home in the first inning after being hit by Hamels, just the latest in an already growing list of accomplishments for the 19-year-old.
Harper came up with two outs in the first and Hamels plunked him in the small of the back.
"I was trying to hit him. I'm not going to deny it," Hamels said. "That's something I grew up watching, that's kind of what happened, so I'm just trying to continue the old baseball because I think some people are kind of getting away from it.
I remember when I was a rookie the strike zone was really, really small and you didn't say anything because that's the way baseball is.
But I think unfortunately the league's protecting certain players and making it not that old-school, prestigious way of baseball."
Harper quickly shrugged off the sting, going from first to third on Werth's single to left. When Hamels made a pickoff throw to first, Harper broke for home and slid in under the tag.
"It's just, 'Welcome to the big leagues,'" Hamel said. "And I think he kind of did that for me."
It was Harper's first stolen base in his eight-game major league career.
In the third inning, Zimmermann hit Hamels in the left leg with one out and a runner on first when Hamels squared to bunt. Home plate umpire Andy Fletcher warned both dugouts.
After the game Harper didn't answer directly when asked if he thought Hamels was trying to hit him, but Johnson thought the move was unintentional.
"I never think it's on purpose. Why would you hit him?" Johnson said. "I didn't think our guy was on purpose either." Hamels (4-1) cruised after Harper's run.
He didn't allow more than one base runner in an inning after the first, and struck out eight against one walk.
The game was close until Philadelphia's six-run ninth inning, including Pence's second homer of the night and sixth this season.
"It's a game we really needed to get," Pence said. "We did a good job today of finding a way to score runs."
Washington starter Jordan Zimmermann (1-3) pitched into the seventh inning, giving up three runs and seven hits and walking four batters as the NL East-leading Nationals ended a four-game winning streak.
Zimmermann had not given up more than one earned run in any of his first four starts this season, but has allowed six over his past two outings. He also had not walked more than two batters in 30 straight starts coming into Sunday's game.
Werth's injury came in the sixth inning.
The right fielder's glove got caught underneath him and bent his wrist backward trying to grab Placido Polanco's sinking liner. Werth stayed on the ground briefly before throwing the ball back to the infield.
He walked off holding his left wrist.
Werth missed the entire 2006 season after an injury to his left wrist which placed his career in jeopardy.
He broke the wrist in spring training 2005 with the Dodgers and played 102 games that season before undergoing surgery to repair a torn ligament in the wrist.