WASHINGTON (AP) -- Before last week's start in New York, Stephen Strasburg noticed his curveball wasn't working the way he wanted it to. He made an adjustment and dazzled the Mets, limiting them to two hits in six innings. Five days later, Strasburg relied on it again.
Against the Houston Astros , the 23-year-old looked unhittable for five innings, struggled in the sixth and watched his team score four runs after he was lifted for a pinch-hitter as the Washington Nationals beat the Astros 6-3 on Monday.
Strasburg allowed just three singles in the first five, but the Astros got to him in the sixth for two runs and three hits.
Strasburg (2-0) walked one and struck out five. He hasn't allowed a home run in 50 1-3 innings - since Aug. 15, 2010. His ERA rose from 0.69 to 1.42.
"I thought I could get another inning out of him - until that rough inning," manager Davey Johnson said.
Steve Lombardozzi had three singles and a two-run double in the sixth off Kyle Weiland (0-2) that gave Washington a 4-2 lead. Ryan Zimmerman followed with a two-run single.
Strasburg used the curveball regularly at San Diego State, and on Monday, he had his best since his Aug. 2010 Tommy John surgery.
"I made an adjustment in New York with it. In the `pen, it wasn't working warming up," Strasburg said.
"I just wanted to go out there and trust it - and it worked pretty well."
Last week, Johnson allowed him to throw a career-high 108 pitches. He wanted Strasburg to throw fewer. Through five innings, he threw 61, but in the laborious sixth, Strasburg had to throw 32.
"In his previous start, I took him longer than I wanted to. It probably took a little bit out of him," Johnson said.
Strasburg wasn't surprised to be pinch-hit for, but didn't come out willingly.
"He knows I want to go out there and stay out there as long as I possibly can. You want to go 7,8,9 innings. I got into a couple of jams that put the pitch count up."
Weiland started for the seventh time in his major league career and is winless in five decisions.
"You try to focus on your own game. Obviously, you know that's in the back of your mind. He's going to go out there and give his best, and it's probably going to be a low scoring game," Weiland said.
After Strasburg left, Sean Burnett got two outs in the seventh, Ryan Mattheus allowed an earned run in the eighth, Tom Gorzelanny finished the eighth, and Henry Rodriguez pitched the ninth for his second save.
In the third, Ian Desmond doubled to left with one out. Lombardozzi bunted, but Weiland threw the ball away, and Desmond scored on the error.
Wilson Ramos hit his first home run with two outs in the fourth.
In the sixth, Jordan Schafer and Jed Lowrie led off with singles. On the ninth pitch of his at-bat, J.D. Martinez walked to load the bases. Carlos Lee flied out to center fielder Rick Ankiel , but Schafer elected not to attempt scoring. Ankiel's threw home was perfect.
After Strasburg struck out Travis Buck , Chris Johnson hit a two-run single to tie the score.
In the bottom of the sixth, Ankiel singled with one out, and with two outs, Roger Bernadina , batting for Strasburg walked. Desmond walked to load the bases, and Lombardozzi, who was starting because Johnson wanted to rest Danny Espinosa , slapped a double to left, and Zimmerman followed with the two-run double.
Weiland pitched 5 2-3 innings, allowing six runs and 10 hits.
The Astros scored their final run in the eighth on a single to Travis Buck and a triple by Johnson - his third hit of the game. They batted 2 for 14 with runners in scoring position.
"With every pitcher I think, as you go and as you get at-bats off of him, your comfort level goes up a little bit. But he's got really good stuff. He throws hard and he's got three really good pitches," Chris Johnson said.
NOTES: Strasburg singled in the fourth inning. He's now 2 for 31 as a major league hitter. ... Nationals RHP Chien-Ming Wang will throw a simulated game in Viera, Fla., on Wednesday, and if that goes well, he'll pitch in a minor league game. Wang has been on the disabled list with a left hamstring injury. ... TV evangelist Joel Osteen threw out the first pitch. He'll be conducting a service at Nationals Park on Apr. 28. ... The Astros have scored at least three runs in every game. ... Houston LHP Wandy Rodriguez (0-1, 2.38 ERA) is scheduled to throw against Nationals LHP Gio Gonzalez (0-0, 3.38 ERA) on Tuesday night.