But the Giants wanted this one, too, and their bullpen came up big in the sixth, seventh and eighth innings as they picked up a rare accomplishment for any team -- a four-game sweep on the road.
"We battled big-time today," closer Brian Wilson said. "We had the opportunity to win that fourth game, and there was that much added emphasis in going out there and getting the job done."
Monday's 3-2 Giants victory was the closest of the series, and the team showed it still had plenty of fight left after a weekend in the scorching Washington heat. The night opened with a strong 6 1/3-inning outing from Matt Cain (3-4).
"I wanted to be aggressive," Cain said. "Make them make mistakes, and not give them free passes."
He gave out just one walk and struck out six. He said before the outing that he had consulted with everybody on the staff he could, from pitching coach Dave Righetti to current hot hand Tim Lincecum.
That advice came in handy as he had a 12-pitch battle with Jesus Flores to escape the sixth inning. With runners on the corners, he delivered strike after strike to Washington's catcher, ultimately foiling him with a slider.
Flores is filling in for injured catcher Paul Lo Duca. Using replacement players was a common theme for the Nationals this week, as their pitchers on Sunday and Monday were both making their season debut -- but manager Bruce Bochy wasn't going to let that detract from what his team accomplished in Washington.
"We know they're a little banged up," Bochy said. "But we had a great series of baseball. [Sweeping four games] is not an easy thing to do."
After the scare from Flores, the Nationals struck twice more. In the seventh, they again put runners on the corners before Cain was removed for reliever Keiichi Yabu, who immediately forced a double play to end the inning.
In the eighth, it was Tyler Walker who got in trouble by loading the bases. Alex Hinshaw came in for one batter of relief, and was pulled for Wilson after allowing a walk.
"That's the ultimate situation for me," said Wilson of entering with the bases loaded.
He ended the inning and then pitched a three-batter ninth to seal up the one-run victory.
The Giants' offense was led by Randy Winn, whom Bochy delights in calling the most underrated player in baseball. The bad news for Bochy is that the secret might be out.
Winn doubled in Ray Durham in the first inning, then picked up the RBI on the team's second run in the fifth, a single that again knocked in Durham. In that sequence, he fouled off four pitches from Tyler Clippard before the hit.
"I was just trying to force him to make a mistake," Winn said.
Clippard's mistakes were exaggerated by his overenthusiasm. In his 2008 debut, he threw 98 pitches but made them last just 4 1/3 innings, as several Giants hitters took him deep into counts.
After the Winn single, Clippard allowed a double to Bengie Molina that was his final pitch of the game, and the decisive third run for the Giants -- just enough for them to turn it over to the bullpen to protect the sweep.
"We got some good pitching today when we needed to, and we battled back," Winn said. "We need a long stretch of good baseball. This is a good start."
It was also a strong outing for Cain, who made sure three runs would be enough for the gritty Giants' bullpen to protect a win.
"It was a great outing," Bochy said. "He went deep and gave us a chance to win. He just looked determined to get it done tonight."
Michael Phillips is a contributor to MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.