Zimmerman and the NL East-leading Nationals try to keep All-Star Matt Cain struggling Thursday night when they go for a sweep of the three-game series.Washington (47-32) matched a season high by moving 15 games over .500 with Wednesday's 9-4 victory. Zimmerman continued his resurgence with a homer, a double and three RBIs for the Nationals, who have won four straight at home and six of eight overall.They have totaled 18 runs and 25 hits in the first two games of this series, the first time the Giants allowed nine or more runs in back-to-back games since Sept. 11-12, 2009."We know that if we come out and play our type of baseball, good clean baseball -- we pitch well and play good defense -- our offense will be there when we need it," Nationals shortstop Ian Desmond told his team's official website.A recent cortisone shot to his ailing shoulder has revived Zimmerman, who is hitting .370 (17 for 46) with five doubles, four homers and 16 RBIs in his last 10 games to raise his average 26 points to .244. The third baseman has enjoyed some success against Cain (9-3, 2.53 ERA), going 6 for 22 with a home run and double."I was playing banged-up for a while there," Zimmerman said. "And when you try to play through things, sometimes it doesn't allow you to do the things you've been doing and that leads to other things and other things. It's definitely a lot better when you show up to the park and you feel healthy every day."Michael Morse, who was on the disabled list for the first two months of the season, also homered Wednesday and is 16 for 35 (.457) with three homers and nine RBIs in Washington's last eight games.The Nationals have averaged 8.6 runs in that stretch, which may make it tough for Cain to have a bounce-back outing. The right-hander had one of his worst performances of the year Friday, giving up five runs and 11 hits -- both matching season highs -- in 6 2/3 innings of a 5-1 defeat to Cincinnati that ended his streak of eight straight winning decisions."Matty was a little off today, a little out of sync," manager Bruce Bochy told the Giants' official website. "He was having trouble getting the ball where he wanted. It's going to happen."The Giants (45-37) have a 5.65 staff ERA in losing four of five since stringing together four straight shutouts.One factor working in Cain's favor, however, is the extra day of rest. He is 3-1 with a 1.49 ERA in five starts with five days' rest, limiting opponents to a .134 batting average while striking out 43 in 36 1/3 innings.Cain is 5-4 with a 3.09 ERA in 11 lifetime starts versus the Nationals, but has been tagged for 11 runs and 18 hits in losing his last two in the nation's capital.Ross Detwiler (4-3, 3.30) has pitched well in both of his starts since rejoining the Nationals' rotation, except for one inning. The left-hander had gone 11 innings without yielding a run as a starter -- 18 innings overall -- before Atlanta scored four runs off him in the seventh inning of Washington's 5-4 victory Friday.Detwiler has gone six starts without a victory since beating Arizona on May 3, and he lost to Cain in his only appearance against the Giants in 2009.Washington has not swept a three-game home series from San Francisco since July 25-27, 2006.