PITTSBURGH - Jeff Bagwell called it a must-win as the Houston Astros' season dwindles to a precious few games. The surprise was how they won it, with a bunch of young players coming off the bench.

Jason Lane's pinch-hit double drove in the go-ahead run in the 10th inning and the Astros, held hitless by Dave Williams for six innings, rallied to beat the Pittsburgh Pirates 5-4 Sunday night.

Eric Bruntlett doubled to start the 10th against Pirates closer Jose Mesa (5-2) and scored on Lane's one-out double, his ninth pinch-hit of the season. Houston stayed a game behind San Francisco in the NL wild-card race. The Giants beat Arizona 5-2.

The Astros averaged more than nine runs while winning 12 in a row entering the five-game Pittsburgh series, but won only once in the first four games - scoring only four runs in the three losses.

Bagwell and manager Phil Garner agreed the Astros couldn't go into their three-game series against NL Central leader St. Louis off four losses in Pittsburgh.

"We had to win and we found a way to win," Bagwell said.

And it wasn't just Bagwell, Craig Biggio, Carlos Beltran and Lance Berkman who rallied the Astros, but callups and rookies such as Lane, Bruntlett and Willy Taveras.

Biggio and Jeff Kent were out of the game following a number of late-inning strategical moves when the Astros came back to win it.

"We used everybody, and it was fun to watch them," Bagwell said. "They're all excited to be here, they've all got a lot of energy and I'm sure it feels good to all of them to have contributed to the win."

After the Astros went ahead, Chad Qualls came in with two on in the 10th and got Abraham Nunez to ground into a game-ending double play for his first career save.

Roy Oswalt left with a 4-2 lead after seven innings and was in position to become the NL's first 18-game winner, but the Pirates scored twice against closer Brad Lidge (5-5), who had converted 21 of 24 save opportunities.

Bobby Hill's RBI single off Lidge in the eighth made it 4-3, and Craig Wilson tied it leading off the ninth with his 27th homer, a drive to center that was his 11th pinch-hit homer in four seasons. He is 2-for-3 as a pinch-hitter this season, with both hits being tying homers in the ninth. He also hit one Sept. 1 in a 5-2, 10-inning victory in Milwaukee.

"He's just phenomenal," manager Lloyd McClendon said.