HOUSTON -- The Houston Astros finally got an easy win after six close games in a row.
Kaz Matsui drove in two runs and Bud Norris struck out seven in six innings for the Astros, who've won 11 of their last 15 home games.
Houston's previous six games had been decided by margins of two runs or less, but the Astros blew this one open with a six-run seventh, capped by Lee's 24th homer.
"I don't remember too many times in recent memory that we felt really comfortable going into the eighth or ninth innings," Berkman said. "That's always nice to play games like that."
Norris (5-3) allowed six hits and won for the second straight time after three consecutive losses. The 24-year-old right-hander has earned a decision in each of his starts since the Astros purchased his minor-league contract on July 29.
"You've just got to trust yourself," Norris said. "The first three [starts], it was more adrenalin. The next three, I was kind of timid to a certain extent. But these last couple, I've really felt like myself again, just playing the game."
Andy LaRoche hit a solo homer for the Pirates, who've lost 12 straight road games and 13 of 14 overall.
The Astros led 3-1 when they loaded the bases in the seventh against Joel Hanrahan. Jesse Chavez relieved and with Michael Bourn batting, a pitch bounced away from catcher Ryan Doumit and Hunter Pence broke for home.
Pence stopped halfway down the line, Doumit threw to LaRoche and the Pirates seemed to have Pence caught in a rundown. But LaRoche's return throw skipped off Doumit's mitt and Pence scored. Doumit was charged with an error.
"It happened so fast," Doumit said. "I should've caught the ball, plain and simple. He threw it and I should've caught it."
Bourn drove in a run with a sacrifice fly and Matsui added an RBI double to make it 6-1. Chavez intentionally walked Berkman before Lee drove a 1-2 pitch into the balcony in left center.
"That's kind of how you draw it up," Berkman said, "get a good strong start and score a bunch of runs. It's a good formula. We haven't had too many like this."
The Astros improved to 41-32 at Minute Maid Park, securing a winning home record for the ninth straight season.
Berkman hit a solo homer off Charlie Morton (3-8) in the first inning, his 20th of the season. Pittsburgh has allowed runs in the first inning in 10 of its last 11 games.
Bourn singled in the third, took second on a wild pitch and scored on Matsui's single to right. Berkman drove in Matsui with a double to the left-field corner for a 3-0 lead.
LaRoche led off the fifth with a homer to left, his ninth of the season. Norris has allowed five home runs in his last three starts.
Morton pitched six innings, allowing only two hits after Berkman's double.
"He threw the ball well," Pittsburgh manager John Russell said. "He gave up three runs in six innings. There isn't anything else you can ask for out of your starter, other than throw a shutout."
Berkman is the third player to reach 20 home runs in every season since 2000. Carlos Lee and Alex Rodriguez are the others. ... The Pirates have been outscored 22-1 in the first inning in their last 11 games. ... Astros RHP Roy Oswalt said he'll make his next scheduled start after giving up six runs and leaving after two innings against Atlanta on Thursday. Oswalt left his previous outing with back soreness, but said Friday that his back wasn't the issue against the Braves. "It was just a bad start," Oswalt said. "It happens. It's a game. They got a few hits and scored a few runs early." ... Doumit was back in the lineup after missing two games with back soreness. He took a pitch off his left knee in the third inning, but stayed in the game.