WASHINGTON -- After his last start, Nationals starter Stephen Strasburg said his mechanics weren't right.
Tuesday night he was finely tuned.
"I just tried to execute pitches better. I wasn't trying to reinvent the wheel," he said. "I think I wanted to go out there and just trust myself, and just have a little bit finer focus. . I feel like I was able to keep the ball down a little bit."
Anthony Rendon added a two-run double for Washington, which has won four straight.
Strasburg (7-6) tied his career high by allowing seven earned runs in 4 2/3 innings in his last start -- a loss in Milwaukee -- and was 0-2 with a 7.27 ERA over his last three.
Tuesday night he struck out eight and walked one while giving up one run. The Rockies didn't get a runner past second until DJ LeMahieu's homer in the eighth.
"I think strike one is probably the biggest difference," manager Matt Williams said. "He got ahead of a lot of hitters tonight. His curveball was effective, his changeup was effective. Went deep in the game. He threw a lot of pitches, but he was in command."
Strasburg was lifted after walking Corey Dickerson with his 111th pitch.
Tuesday night also was a bounce back game for Werth, who was 7 for 52 in his last 13 coming in. He doubled home two runs in the first, another in the fourth and walked twice.
"(I) was here late last night watching video with Rick Schu, our hitting coach," Werth said. "Today, had a pretty good mindset going into the game and we made a minor adjustment, just kind of shorten (my swing) up a little bit."
Washington has scored seven runs in three straight games, albeit the last two against the pitching staff with baseball's worst ERA.
"There's not an easy out one thru eight," Strasburg said. "It's our job as pitchers to go out there and keep it close and let our (hitters) go out there and win the game."
Christian Friedrich (0-3) allowed five runs in 3 1/3 innings for Colorado, which has lost 13 of 15.
"Every day you can't worry about what happened yesterday," Rockies first baseman Justin Morneau said. "You're not going to change it. If you start thinking that way, that's when you get in trouble. When you can put today behind us and come back and try and win a game tomorrow and start over, that's what good teams are able to do."
Friedrich was making his third start since being called up June 21 and struggled once again, allowing five hits while walking four and striking out four. Overall, he's given up 14 earned runs and 21 hits in 13 1/3 innings.
He struggled with his control early and the Rockies were quickly behind.
"Tough to play from behind against Strasburg. We got down early, made it tough," Rockies manager Walt Weiss said.
Strasburg helped Washington break it open when he doubled past a diving Brandon Barnes in right with one out in the fourth.
Span singled Strasburg to third and moved to second on a wild pitch. Rendon then greeted reliever Chad Bettis with a double to left, increasing the lead to 5-0. Werth singled to score Rendon and later came home on a wild pitch.
In middle of 20 straight days with a game, Weiss rested SS Troy Tulowitzki and OF Charlie Blackmon. Blackmon grounded out as a pinch hitter in the eighth. ... Rockies LH Brett Anderson (broken finger), on the DL since April 13, is scheduled to make his first rehab start Wednesday for Triple-A Colorado Springs. ... The Nationals, after allowing 19 unearned runs in March/April and 13 in May, set a new club record by allowing just two in June. ... Colorado's LH Tyler Matzek (1-2, 4.24) opposes RH Doug Fister (6-2, 2.83) in Wednesday's series finale.