The Rockies scored the go-ahead in the eighth inning. Clippard started off the inning by walking pinch-hitter Seth Smith. Carlos Gonzalez followed and singled to right field to put runners on first and second.
Pinch-hitter Dexter Fowler came to the plate and bunted the ball in front of catcher Ivan Rodriguez. It looked like Rodriguez had a shot to get the force at third base, but Rodriguez threw to first instead for the out.
Rodriguez said after the ball bounced high into the air, there was no chance for him to get Smith at third.
"For me to be able to throw to third base, I might rush it and throw the ball away. I was trying to get an out and that was it," Rodriguez said.
Brad Hawpe was the next hitter and hit a sacrifice fly to left field to bring home Smith. For Clippard, he said the key to the inning was walking the leadoff hitter.
"I felt really good today. I made some good pitches," Clippard said. "After the leadoff walk, I needed to bounce back. I left the changeup up to Gonzalez. I made some really good pitches to Hawpe. I needed a strikeout there. I was trying to get the changeup out of the zone, but it was a little too high for a strikeout pitch. He was able to get a bat on it."
Clippard pitched on three days' rest and manager Jim Riggleman felt that Clippard might have received too much rest.
"I think he's had too many days off, lately," Riggleman said. "He hasn't pitched since Wednesday in New York. He has been up a time or two. He is throwing the ball OK. He is just not locating it. He doesn't quite have the finesse on his changeup, which has been a savior for him."
But Clippard said he needed the rest. It's not a secret that many believe Clippard has been overworked during the first part of the season.
"I needed the rest. I was pitching a lot. I felt really good today. When you are in a tied ballgame, you can't let the leadoff guy on. That's what I did today. It happens," Clippard said.
Left-hander Scott Olsen continues to show that he is fully recovered from left shoulder surgery. On Sunday, he gave up one run in 6 2/3 innings and lowered his ERA to 3.15. In his last five starts, Olsen has allowed four earned runs in 32 1/3 innings for a 1.12 ERA in that stretch.
Rockies manager Jim Tracy talked about the great slider Olsen threw in the game.
"Give Scott Olson a lot of credit," Tracy said. "That guy had a terrific slider to both left- and right-handed hitters in our lineup, and so offensively we had to do just enough to win, and let pitching and defense take over, and that's exactly what happened."
The Nationals gave Olsen a 1-0 lead in the first inning off left-hander Jeff Francis, who pitched in his first game since 2008 after recovering from shoulder problems. Cristian Guzman hit a sacrifice fly to center field to score Nyjer Morgan.
Francis would go on to pitch seven solid innings and give up the one run on seven hits. He ended up with a no-decision.
"You have to give credit to the guy," Rodriguez said about Francis. "He threw great. He used both sides of the plate. He used all of his pitches. He just located them very well. Sometimes you have to give them credit, too.
"He did great. It's good to see a kid like that come back from an injury like that to give the Rockies seven innings. Sometimes you have to say, 'Good job.'"
The Rockies tied the score in the top of the second inning. With one out, Miguel Olivo brought home Troy Tulowitzki with a sacrifice fly.
Washington had another opportunity to score off Francis, but couldn't get the job done. In the top of the seventh inning, the Nationals had runners on first and second and nobody out. Olsen tried to advance the runners, but he struck out trying to bunt the ball down the third-base line.
After that, Morgan struck out looking, and Ian Desmond popped up to shortstop Tulowitzki to end the inning.
"That was our best chance to score, and I didn't do the job," Olsen said. "If I get that ball down, it's a different game. I was able to do my job on the mound, but not at the plate."
Washington has a three-game losing streak for the first time this season and dropped its record to 20-18. Clippard said don't look for the streak to last long.
"We had some heartbreaking losses since we've been in Colorado, but we are still playing well. We have a good outlook on everything that is going on right now," Clippard said. "Nobody is really panicking or anything like that. We have played solid baseball, and we are going to continue to do so. It has been tough the last three games. That's baseball. It's happens."
Bill Ladson is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.