San Francisco, CA -- (Sports Network) - Matt Cain threw a four-hit shutout and Dave Roberts singled home the winning run in the eighth inning as the San Francisco Giants completed a three-game sweep over the Washington Nationals with a 1-0 victory that lasted a mere two hours.

Cain (6-8) spearheaded the Giants' first home sweep of the season, as the club completed a seven-game season-series sweep of the Nationals. The righty did not walk a batter and managed four strikeouts, tossing 81 of his 113 pitches for strikes in his first shutout since 2006.

Roberts, in his first start since April 7, was 2-for-4 at the plate, while Aaron Rowand added two hits for San Francisco, which was swept in three games by Milwaukee coming into the series.

Tim Redding (7-5) threw the first complete game of his seven-year career, but took the loss after allowing a run on seven hits with no walks and five strikeouts. Ryan Zimmerman and Cristian Guzman both doubled in the Nationals' sixth loss in eight games.

"It was just one of those days everything was clicking and we fell short 1-0," Redding said. "When you get into a rhythm like that, these are the types of games, two hours, 1-0 ballgame, complete games by both guys, they don't happen too far in between all the other games. They're kind of nice but it sucks we're on the wrong end."

After 7 1/2 scoreless innings the Giants played small ball to account for the game's only run. Steve Holm led off the eighth with a single to left and Cain moved pinch-runner Eugenio Velez into scoring position with a sacrifice bunt.

Roberts went down 1-2 in the count, but managed to punch a single past a diving Guzman at short, and the speedy Velez scored without a throw.

"I just feel like a kid again," Roberts said. "The excitement, the adrenalin and seeing fans cheering for something you did out on the field. It's fun and that's what it's all about."

Cain came out in the ninth to complete his shutout. After fanning Jesus Flores, Willie Harris beat out an infield single and Guzman doubled down the left field line.

After a brief coaching visit to the mound, Giants manager Bruce Bochy left Cain in the game and the decision proved correct. Zimmerman's pop fly to right wasn't deep enough to score a run, and Austin Kearns flied to right to conclude the pitching masterpiece.

"It was big for Dave to come up with that hit in the eighth inning, and to be able to go ahead and get those last two outs in the ninth inning was big especially the situation we were in," Cain said.

Game Notes

The Giants are still just 20-31 at home this season...The 36-year-old Roberts was sidelined for most of the year after having knee surgery in April...Redding is still winless in eight appearances -- six starts -- against San Fran...It was the Giants first season sweep against an opponent since taking all six games against the Mets in 2002.