WASHINGTON (AP) — The Washington weather and the Washington Nationals bats combined to derail the progress Tim Lincecum made in his two previous starts.

All-Star shortstop Ian Desmond hit his 14th home run, and the Nationals became the latest team to beat up on Lincecum, pounding the struggling right-hander hard early and often Tuesday night in the San Francisco Giants’ 9-3 defeat.

Pitching with a game time temperature of 94 degrees, Lincecum (3-9) allowed eight runs and nine hits in 3 1/3 innings. Seven runs were earned, making it the worst start ERA-wise in his major league career.

“He showed the effects from throwing a lot of pitches early in this heat and couldn’t hold ‘em. He had trouble getting the ball where he wanted it,” Giants manager Bruce Bochy said.

The two-time Cy Young Award winner started to look his old self again in his previous two starts, but Tuesday’s effort ballooned his ERA to 6.08.

“I think it’s just coming here and dealing with the heat — it’s not like it’s anything different than what we’ve dealt with — it just got the better of me today a little bit. They made me work and made me pay for it,” said Lincecum, who threw 87 pitches.

Lincecum retired three straight hitters after Steve Lombardozzi led off the first with a single, but Washington scored two in the second, three in the third and three in the fourth. Every player in the Nationals starting lineup had at least one hit off Lincecum except catcher Jesus Flores.

“My stuff was just a little flatter today, not as crisp coming out, with the exception of a couple of batters in that first inning. I thought that was the difference,” Lincecum said.

Lincecum threw seven scoreless innings in his last start a week ago against the Dodgers.

“Obviously it’s easy to look at what happened today and think I took a step back,” he said. “I think that’s where I’ve been wrong, just looking at all the negatives and whether or not it was a step forward or a step back as opposed to where I can go from here. Yes, it’s a bad outing, but the next outing has nothing to do with today. It’s about getting better in the next four days.”

The opener of the three-game series between first-place teams was barely a contest. Jordan Zimmermann (5-6) pitched a rain-shortened six innings and again enjoyed the generous run support that had evaded him for so long, ensuring the Nationals would wake up on the Fourth of July with a 3½-game cushion over the New York Mets atop the NL East.

Desmond, one of a trio of players the surging Nationals are sending to the All-Star game next week, hit a two-run shot to left field in the third. He also has an eight-game hitting streak, including extra base hits in six of those games.

Zimmermann was one of four players to double off Lincecum, who was removed after sandwiching walks around Bryce Harper’s double to load the bases with one out in the fourth. Reliever George Kontos allowed all three inherited runners to score, putting the Giants in an 8-0 hole.

The Giants scored a pair on Zimmermann in the fifth on a single by Gregor Blanco, but it took a summer storm to send the Nationals starter to the showers. He was on the mound when rain started to fall in the seventh inning and was replaced by reliever Ryan Mattheus after an 85-minute delay.

Notes: Blanco had three singles and a stolen base. ... The teams have an 11:05 a.m. first pitch for the Fourth of July. ... Desmond is 9 for 12 lifetime against Lincecum.