HOUSTON (AP) -- Josh Anderson isn't playing like a guy who has 15 games in the major leagues under his belt.
The rookie reached base six times and drove in three runs, and Houston piled up 22 hits to help Brandon Backe win for the first time in more than a year as the Astros routed the Pittsburgh Pirates 15-3 on Sunday.
Anderson, who played 131 games with Triple-A Round Rock before arriving Sept. 1, had five hits and a walk to set a club rookie record for a nine-inning game. Joe Morgan reached base six times as a rookie against Milwaukee on July 8, 1965, in a 12-inning game.
"I'm a little bit surprised," said Anderson, who started his third straight game in center field and raised his batting average to .500. "I had a six-hit game in A-ball in 2004 and I had five hits one other time in the minors.
"It was just one of those days when you feel good, you feel locked in. It's hard to describe. I guess it's like a basketball player hitting several 3s in a row."
It certainly impressed interim manager Cecil Cooper.
"He's an exciting young player," Cooper said. "Hopefully he'll get a chance to continue. It's pretty hard to bench a guy who had five hits. He'll definitely play tomorrow."
On the season, Anderson has played in 9 games, going 9-18 (.500) with 5 RBI's and 4 runs scored.
Chris Burke had three hits and four RBIs and Ty Wigginton had a home run, double and single as Houston set a season-high for runs to win its second straight. The 22 hits were a club record for a home game.
Backe (1-1), who had Tommy John surgery Sept. 6 of last season, went six innings in his third start of the year and allowed two runs and three hits. He walked two and struck out two.
The right-hander, who started out as an infielder in the Devil Rays organization, also doubled, singled and scored twice.
Houston scored five in the first on Anderson's RBI double, a run-scoring single by Mark Loretta and Ransom's homer.
After Jack Wilson hit his 12th homer of the season in the second, Anderson's RBI single in the bottom half of the inning made it 6-1.
The Astros added five more and chased Maholm in the third inning. J.R. Towles had an RBI single and Burke a two-run single. Reliever Juan Perez then entered and gave up three straight singles, the last a two-run hit by Carlos Lee.
Carlos Maldonado hit a solo homer in the seventh off reliever Mark McLemore. It was Maldonado's first career homer.
Burke hit a two-run homer in the eighth. It was his sixth home run of the year.