Pirates closer Joel Hanrahan celebrates with catcher Ryan Doumit on Monday after getting the final out of the ninth inning in a 3-1 victory over Houston.

PITTSBURGH — Maybe all James McDonald needed to pitch deep into a game was a little urging from Mother Nature.

Working quickly in a steady rain, McDonald pitched into the eighth inning to lead the Pittsburgh Pirates to a 3-1 win over the Houston Astros on Monday.

“Great tempo, rhythm, all of it,” Pittsburgh manager Clint Hurdle said. “This was a big step forward for him.”

McDonald can be dazzling at times with his electric 95 mph fastball but often struggles with his command, making it difficult to last into the later innings.

There were no such issues against the Astros. McDonald (9-7) threw 91 pitches before leaving with one out in the eighth following the second-longest outing of his career. He may have made a run at a complete game if not for a pair of walks in the eighth.

“I feel like things are going in the right direction right now, just getting ahead of guys,” McDonald said. “I think that’s the big key to the success today.”

The game was delayed 56 minutes by rain and was played in a steady drizzle as both teams hustled to avoid a rainout. The grounds crew frequently added fresh dirt to the pitcher’s mound to keep it from getting muddy, though portions of the warning track were under water by the late afternoon.

“No one wants to pitch under those circumstances,” catcher Ryan Doumit said. “It’s hard enough to pitch as it is but with a wet mound it’s even harder. For him to go out and pitch the way he’s pitched just gives you a glimpse of what he’s capable of.”

Doumit had three hits, Josh Harrison went 2 for 3 and Derrek Lee hit his 16th homer as the Pirates won for the third time in four games. Joel Hanrahan worked the ninth for his 35th save.

“It was just one of those days where it was not a fun day out there, pretty much,” said Houston’s J.D. Martinez, who struck out three times. “When you’re facing a guy like (McDonald) who’s making good pitches, that rain on you all game, it’s just tough to score runs, tough everything.”

McDonald gave up three hits, struck out six and walked three to outduel promising rookie Henry Sosa (2-3), who sparkled in a victory over the Pirates a week ago.

Sosa wasn’t hindered by the miserable conditions but the Pirates were able to do just enough to get by.

“I felt good today and I feel comfortable all the time,” Sosa said. “Every game (I) feel more comfortable.”