WASHINGTON (AP) -- In the fifth inning, Randy Winn fouled off four straight pitches before hitting a changeup through the middle, driving in the go-ahead run.
One long turn at the plate ended successfully, the other in failure. The way the San Francisco Giants and Washington Nationals have been playing lately, it only made sense that those were the defining moments of a one-run game.
The Giants completed a sweep of the Nationals on Monday, winning 3-2 as they start to turn around a season that was heading nowhere only a few weeks ago. San Francisco outscored Washington by a combined 25-6 to complete their first four-game whitewash of the franchise since 1994 -- more than a decade before the team moved from Montreal to Washington.
"We had the opportunity to win that fourth game," said closer Brian Wilson, who worked 1 1/3 innings for his 18th save. "So there was that much added emphasis out there to get the job done."
San Francisco has won six of eight overall, and its seven-game road winning streak is its longest since 2003.
Cain (3-4) allowed one run and eight hits over 6 1/3 innings to get his first victory since May 13. Meanwhile, his teammates made a case for a new baseball axiom: The fifth inning is a good time to pick on a rent-a-pitcher from the minors.
For the second straight day, the Giants came alive in the fifth against a starter making a one-game visit from Triple-A Columbus. Consecutive hits by Ray Durham, Winn and Bengie Molina chased Tyler Clippard (0-1), who was promptly sent back to the minors after the game.
On Sunday, the Giants used a four-run fifth to chase Garrett Mock, who was making his major league debut because of an injury to Odalis Perez. Mock was optioned back to Columbus after the game and replaced by Clippard, who filled a hole in the rotation created by an unexpected doubleheader late last week.
Clippard's only previous big league experience was a 3-1 record in six starts for the New York Yankees last year. Making his Nationals debut, he allowed three runs and five hits with four walks and six strikeouts in 4 1/3 innings. He was holding his own in a 1-1 game until Durham doubled to the right-field corner with one out in the fifth.
Then came Winn's big at-bat. He battled and battled until he got his hit, driving in his second run of the game.
"I had two strikes, so I was just trying to put a good swing on the ball," Winn said. "I was able to foul off some tough pitches. I was just trying to get a mistake there. If he makes a good pitch down, then I'm probably out, but the pitch was a little bit up."
Molina then doubled to the wall in left to score Winn, giving the Giants a 3-1 lead -- enough to beat the worst hitting team in the league.
"The fastball command really wasn't there," Clippard said. "I'm a changeup pitcher so I need my fastball for it to be an effective pitch. It wasn't there and it cost me."
The Nationals have lost eight of nine, scoring three runs or fewer in all the losses. They suffered the ignominy of having two runners caught stealing in the first inning; Elijah Dukes and Lastings Milledge were both thrown out trying to swipe second.
Washington's only runs came on a sacrifice fly by Flores in the fourth and a throwing error by catcher Molina in the eighth. Cain worked out of a one-out, first-and-third jam in the sixth with the strikeout of Flores on the 12th pitch.
"Somebody was going to have to give in, and I didn't want it to be me," Cain said. "I kept thinking to myself, 'OK, I'm going to get him out, I'm going to get him out, I'm going to get him out.'"
Cain was replaced after hits by Felipe Lopez and Wily Mo Pena put runners on first and third with one out in the seventh, but reliever Keiichi Yabu got pinch-hitter Aaron Boone to hit into a double play.
Molina threw a wayward pickoff attempt in the eighth to allow Milledge to score from third. The Nationals loaded the bases with two outs later in the inning, but Wilson entered and got Lopez to fly out.
The Nationals ended the game by grounding into a double play.
"Hits don't win games," manager Manny Acta said. "Hits with runners in scoring position win games. We couldn't get them when we had guys in scoring positions."
To replace Clippard, the Nationals reinstated INF Ronnie Belliard from the 15-day disabled list. Belliard had been sidelined since May 16 with a left calf strain. ... The Nationals, playing in a new ballpark, drew 26,209 to pass the one million mark for the season. They are averaging around 29,000 at Nationals Park, about 4,800 more than they averaged last year in their final season at RFK Stadium.