Molina had his fifth career multihomer game and second this season, which he also accomplished April 8 against San Diego. Fred Lewis hit his first career leadoff home run when he connected to right on a 1-0 pitch from Jason Bergmann (1-7).
Zito (5-12) won back-to-back decisions for the first time all year, getting plenty of offense in the process. He hadn't done so since winning his final two outings of 2007. He received cheers instead of jeers from the fickle San Francisco fans. Zito struck out five and walked three in six solid innings, allowing three runs and seven hits.
The last time the Giants hit three home runs in a game was May 23, helping Zito to his first win of 2008 after an 0-8 start. San Francisco had hit only three homers in its previous 18 games.
Omar Vizquel added an RBI double in the fourth only a few hours after manager Bruce Bochy and general manager Brian Sabean told the 11-time Gold Glove shortstop, 41, that rookie Emmanuel Burriss would get significant playing time at the position during the season's second half. Aaron Rowand's RBI single in the eighth provided an insurance run.
San Francisco ended a four-game home losing streak with just its fifth win in the last 19 games in the club's waterfront ballpark. The Giants had three home wins in May and June and now four so far in July, improving to 18-30 at home.
Willie Harris hit a solo homer and Paul Lo Duca had an RBI double and run-scoring single for the Nationals, who had scored 29 runs in their first three games after the All-Star break.
Tyler Walker got Lo Duca to fly out to center in the eighth, then All-Star closer Brian Wilson recorded the final three outs for his National League-leading 26th save in 28 opportunities.
Eugenio Velez began his stint as San Francisco's new regular second baseman, two days after the Giants dealt Ray Durham to the Milwaukee Brewers for two minor leaguers. Velez singled and stole his ninth base in the first.
Notes:@ At 16-15, the Nationals are one of three NL teams with winning records at AT&T Park. The Dodgers and Pirates are the two others. ... Zito also beat the Nationals on June 8. ... Giants INF Kevin Frandsen, recovering from a ruptured left Achilles' tendon that could cost him the season, hit live batting practice in the outdoor cage for the first time. "It's just one of those things. It's another step," he said. ... San Francisco will take infield practice once a series, including on the road -- and such practice is rare these days during the season. "It's more a response that when you have young players you want to continue to work with them," Bochy said. ... Nationals SS Cristian Guzman agreed to terms on a $16 million, two-year contract extension that takes him through the 2010 season. He went 0-for-4 with a walk and grounded into a double play. ... Bergmann is winless in 11 starts since beating the Mets in New York on May 15.