HOUSTON — The Cincinnati Reds try not to worry about what other teams are doing while they’re playing.

It was hard for them to ignore the NL Central-leading Cardinals’ loss on Friday as they were beating the Houston Astros.

The Reds got the 6-4 victory thanks to Jay Bruce’s go-ahead double in the eighth inning, and wound up just half a game behind St. Louis.

“We’re trying not to scoreboard-watch too much, but it’s obvious that we do,” Bruce said. “It’s good for them to finally lose some. They were hot for a while so hopefully we’ll just continue rolling.”

Tim Byrdak (1-1) allowed consecutive singles by Joey Votto and Jonny Gomes before giving up Bruce’s grounder that rolled just inside the right field line.

Hunter Pence had four hits, including a home run, and drove in three runs for the Astros.

Nelson Figueroa replaced Byrdak and struck out Miguel Cairo before a sacrifice fly by Drew Stubbs added a run.

Angel Sanchez singled before Lance Berkman walked with one out in the ninth inning. But closer Francisco Cordero retired the next two batters for his 27th save.

The Astros loaded the bases with one out in the eighth inning before Nick Masset struck out Pedro Feliz. Masset was replaced by Arthur Rhodes, who retired Anderson Hernandez to end the inning.

Logan Ondrusek (1-0) pitched a scoreless seventh inning for his first major league win.

“Our bullpen was a little spent tonight, (Jordan) Smith had gone two days in a row and (Bill) Bray had gone three days in a row and Masset went yesterday, so we needed to close that game out,” manager Dusty Baker said. “We didn’t have any length had they tied that game up and went to extra innings. So the guys came in and they knew what was at stake, they knew the Cardinals had lost, they knew that we were short in the ’pen and the guys came through.”

In the sixth, Pence’s two-run homer to the Crawford Boxes in left field scored Carlos Lee and tied the game at 4.

“You got a hot Hunter Pence tonight. That was just good hitting,” Baker said. “Every time a guy hits a home run it’s not necessarily a mistake like people think. He knows that it’s good hitting on his part.”

Houston manager Brad Mills agreed.

“Hunter getting four hits like he did, that’s special,” he said.

Keppinger followed that shot with a double that dropped just short of the wall in left center field, but Reds starter Travis Wood retired the next three batters.

Joey Votto had a solo homer that landed in the first row in right field to make it 4-2 in the fifth inning.

Houston starter Bud Norris sailed through the first three innings, retiring nine of the first 10 batters, before he got into trouble in the fourth. Orlando Cabrera singled before consecutive walks by Votto and Jonny Gomes loaded the bases. A sacrifice fly by Bruce scored Cabrera to tie it at 1. Norris then hit Cairo with a pitch before Votto was out at home on a force out.

Ryan Hanigan hit a two-run single to give Cincinnati a 3-1 lead.

“I got a little sloppy there, but I made some pitches,” Norris said. “You got to make pitches and compete and battle. I got to come out tomorrow and get better. There’s been a bunch of starts that have gone that way, but I’m learning and trying to get better every day.”

Pence drove in a run with a single in the first inning that made it 1-0. Pence got Houston within 3-2 when he beat the throw home on a sacrifice fly by Chris Johnson in the fourth inning.

Wood gave up nine hits and four runs with four strikeouts in six innings.

NOTES: Astros ace Roy Oswalt addressed reports that he has demanded that any trade require a team to pick up his $16 million option for 2012. “The money part I can work out with anybody,” he said, without confirming or denying those reports. … Gary Matthews Jr., who is currently playing for the Reds’ Triple-A Louisville, can opt out of his deal if he isn’t brought up to the majors by Saturday. Baker didn’t say if he would be brought up, but did say he hopes he doesn’t opt out.