PITTSBURGH - This figured to be as easy as it gets for Roger Clemens.

Opposing pitcher Ian Snell had zero victories in the majors, or 340 fewer than Clemens. The Pittsburgh Pirates owned the NL's worst record and had never beaten Clemens. Their lineup had four rookies and two second-year players, including one with eight career at-bats and two others with fewer than 210.

Mismatch, it was.

Snell pitched like the Clemens of old, limiting the Houston Astros to three singles over eight innings. Clemens pitched like, well, an old Clemens in the Pirates' 7-0 victory Monday night that ended Houston's five-game winning streak.

The Astros fell back into some old habits as their NL wild-card lead over idle Philadelphia was trimmed to one game. They were shut out for a major league-high 17th time, nine with Clemens on the mound, and a third time in Pittsburgh.

"We've just got this demon hanging over our head, and it's a zero," manager Phil Garner said.

Snell (1-2) didn't have any problems, despite previously being 0-3 with a 12.38 ERA in four major league starts. He cruised through the Houston lineup, leaving only because he threw 103 pitches through eight innings.

"I faced Chris Carpenter in my last start, and he's probably going to win the Cy Young Award, so it didn't faze me at all," Snell said of facing Clemens. "But I'm going to cherish this for a long time."

Clemens (12-8), never throwing harder than 92 mph, didn't last nearly as long as Snell. He fell behind 2-0 on Jason Bay's RBI single in the third and Freddy Sanchez's third homer, in the fourth, then gave up four more runs - two earned - before leaving with two outs in the sixth.

The customary lack of run support didn't bother Clemens nearly as much as his own inability to keep the game close. He allowed 11 hits, the most he's permitted since giving up that many on April 15, 1999, against the Orioles for the Yankees.

"My main concern is when it's 2-0, I've got to keep it at 2-0," Clemens said. "It gives us a little more of a chance. To give up four more runs, that isn't going to get it done. I don't care who you're facing or who you're playing, it's not going to get it done."

Clemens beat Florida 10-2 on Wednesday, hours after his mother, Bess, died. Despite the emotional stress and sadness, he said his mother's death didn't affect his preparation for this start.

"I'd be cheating everyone here, the staff and rest of my teammates, if I wasn't able to stay on top of my work," Clemens said. "It was almost like therapy, to come back and get in an environment I'm comfortable with."

Even if his 670th career start was his first in Pittsburgh, the only major league city in which he had never pitched.

Maybe he shouldn't have waited so long, given his inability to master a lineup that had only 10 previous hits against him. The Pirates' lineup included second baseman J.J. Furmaniak (eight previous at-bats) and first baseman Brad Eldred (60 strikeouts in 154 at-bats).

Bay, previously 0-for-8 against Clemens, went 2-for-3 with an RBI against him, and Sanchez, previously 0-for-3, went 3-for-3 with a homer and two doubles.

To Bay, it wasn't the Clemens he saw before, even though the Pirates won the previous two games he started against them this season. He didn't figure in the decision in either.

"That's what we were saying, he never misses up in the strike zone," Bay said. "But he left some pitches high, and we did a good job of hitting the pitches he made mistakes on."