TORONTO -- Vernon Wells wasn't sure how to react after hitting a home run for the first time in 88 at-bats.
"I didn't know what to do when I hit it," Wells said. "I was kind of shocked, honestly."
Wells, who signed a seven-year, $126-million contract extension in the offseason, homered for the first time since May 20 at Philadelphia. It was his sixth homer of the season.
"It felt really good," Wells said. "When I hit it, I looked at the ball and said 'Man, I haven't seen a ball fly off my bat like that for a while.'"
Wells followed up a three-hit game Friday with an RBI single in the first, a homer in the third and a bases-loaded walk in the fourth.
"Last couple of days, he's been swinging it," manager John Gibbons said. "He's big for our team, no question."
Wells, who boosted his average to .258, said he has been seeing the ball better the past two games and has tried to stop swinging too soon.
"I go back and look at highlights and I'm hitting outside pitches out in front of the plate," Wells said. "If I let it travel another six to eight inches, I'm going to barrel that ball into right-center. Everything has been out and around the ball instead of down through it."
Frank Thomas hit a two-run single in the third and Troy Glaus was hit by a pitch with the bases loaded in the fourth as Toronto won its third straight, matching a season-high set four times previously.
Toronto's offense is ninth in the American League in runs, but has scored seven runs in each of its past three games.
"We need to give our pitchers a break," Wells said. "They've been carrying us for the last month or so. We need to go out and continue to score runs early."
Marcum (4-2) improved to 3-0 with a 2.38 ERA in seven starts since joining Toronto's rotation on May 13.
"He's been unbelievable since he's been in the rotation," Wells said. "He's throwing strikes, he's working quickly. He's been good for us."
The 25-year-old right-hander struck out the side in the first and fourth innings, walked three and gave up two runs and three hits, including two home runs.
Nationals manager Manny Acta said Marcum kept his team off-balance with a good changeup.
"He did a tremendous job," Acta said. "He's got good off-speed pitches and good command of them. We couldn't adjust to him the whole day."
The changeup was the first pitch Marcum learned as a teenager and he has come to rely on it.
"I'm almost more comfortable throwing the changeup than I am the fastball," Marcum said. "It just feels so comfortable in my hand."
"It makes your fastball that much better," he added. "I don't throw 100 miles per hour like A.J. (Burnett). I can throw the changeup to keep them off balance and then it makes my 88 mile-per-hour fastball look that much better."
Gibbons knows the changeup can be a valuable part of any pitcher's arsenal.
"If you've got a good one, it's the best pitch there is," he said.
Zimmerman added an RBI-single in the eighth off reliever Casey Janssen, who recorded the final five outs.
Making his sixth start, Washington right-hander Levale Speigner (2-3) allowed seven runs and 10 hits in 3 1/3 innings. He walked two and struck out one. Speigner's ERA rose to 8.76.
"He made way too many mistakes over the plate, but he's a double-A kid that we've got up here as a Rule 5 so we're going to have to take his lumps," Acta said.
The loss denied Washington the chance to extend its run of four straight series victories on the road.
Nationals second baseman Felipe Lopez, a former Blue Jay, struck out four times in four at-bats.
- Washington batters have hit 24 home runs in the team's past 24 games.
- Toronto has won six straight over Washington dating back to 2005.
- Playing for Triple-A Columbus, Washington minor league outfielder Brandon Watson doubled in the fourth inning Saturday, extending his hitting streak to 42 games and matching the International League record set by Jack Lelivelt of the Rochester Hustlers in 1912.