WASHINGTON — Wow. The Washington Nationals have scored a bunch of runs for Jordan Zimmermann in back-to-back starts. They must really be serious about this first-place thing they’ve got going.

Tim Lincecum also has something serious happening. His ERA is over 6.00 after one of the worst games of his career.

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

Zimmermann (5-6) is finally learning what it’s like to pitch with a comfortable lead. He went a rain-shortened six innings to win at home for the first time since last August.

“It’s nice. They’re starting to come around and score early,” Zimmermann said, “and give you a little room to breathe out there.”

Zimmermann has gone at least six innings in every game this season and leads the team with 14 quality starts, but the National League East leaders are only 9-7 when he pitches.

The tide has turned in his past two starts, an 11-5 win over Colorado to go with Tuesday’s knockout of the Giants. He had been winless in his past eight starts at National Park, with his team giving him a combined 10 runs of support while he was in the game.

“He’s obviously the bulldog of our staff,” Desmond said. “That’s what kind of hurts when you don’t score runs for him.”

The Nationals have started hitting the ball better overall in the past few games, sustaining the momentum from that offensive spree in the thin air of the Rocky Mountains. Combine that with a pitching staff that leads the majors in gobs of categories, and it makes Washington look quite formidable.

“If they keep hitting the way they’re hitting now, I don’t see why we can’t just run away with this in the second half,” Zimmermann said. “If we keep pitching the way we are, it’s going to be tough to beat us.”

The Giants scored a pair on Zimmermann in the fifth, but it took a summer storm to send him 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.

Lincecum (3-9), by contrast, looked very beatable, allowing 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. The two-time Cy Young Award winner had started to look his old self again in his previous two starts, but Tuesday’s effort in the heat and humidity — it was 94 degrees at first pitch — 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,” Lincecum said. “They made me work and made me pay for it.”

Lincecum gave up 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 except catcher Jesus Flores, with even Zimmermann contributing an RBI double in the second inning.

“Obviously it’s easy to look at what happened today and think I took a step back,” Lincecum 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.”

Desmond had the biggest hit, a two-run shot to left field in the third. He had already topped his best power season in the majors, and now he’s surpassed the 13 homers he hit with Single-A Potomac in 2007. He is also 9 for 12 lifetime against Lincecum.