HOUSTON -- It took one swing for Mark Saccomanno to make a name for himself.
"I went up there very nervous. I don't even remember it -- my legs were so weak," Saccomanno said. "It was a great feeling to hit it out. It was like a dream."
Saccomanno hit a solo shot in the fifth inning, becoming the fourth Houston player to homer in his first big league at-bat. The Astros have won three straight and 11 of 12 to move 10 games over .500 for the first time this season. They are five games behind Milwaukee, which leads the NL wild-card standings.
Called up from the minors earlier in the day to help fill in for injured third baseman Ty Wigginton, Saccomanno batted for pitcher Alberto Arias in a scoreless game and drove Ian Snell's pitch into the right-field bullpen.
"He walks up there like he isn't nervous at all. And he just hits it out," Houston manager Cecil Cooper said.
Saccomanno was in Austin at 2:30 p.m. on Monday when he got the call to join the Astros. He hopped a flight to Houston at 4:30 and arrived just in time for the game.
"I didn't get a chance to get any swings before the game," Saccomanno said. "So I went down to the batting cage in the second inning with (coach) Dave Clark. I was thinking about what to do and I said if I got in I might take a pitch. He said, 'If you do, I'll fine you,' and I knew he would."
The home run triggered a three-run inning for the Astros. The next four batters got hits, including RBI singles by Miguel Tejada and Lance Berkman.
"Who would have thought that a guy coming off the bench would do that?" Snell said. "I threw him a fastball down and away and he went and got it."
Saccomanno batted .297 with 27 home runs and 84 RBI for Triple-A Round Rock this season.
"He showed up about 6:30 and jumped in a uniform and had a pretty good start," Cooper said. "He really made it big. We were looking a little stale until he got that hit."
Saccomanno became the 22nd player to hit a home run on his first pitch in the majors.
The last Houston player to homer in his first career at-bat was Charlton Jimerson on Sept. 4, 2006, at Philadelphia.
Kevin Kouzmanoff was the last player to hit a home run on his first pitch in the majors. He did it for Cleveland on Sept. 2, 2006, becoming the first big leaguer to hit a grand slam on his first pitch.
Arias (1-0) gave up two hits in five impressive innings. It was his first major league start after 18 relief appearances with Colorado.
"He gave us a real solid start," Cooper said. "He threw hard and he pounded the bottom of the zone. That's what we wanted out of him."
Arias started strong, striking out five of his first six batters. He didn't allow a hit until Nyjer Morgan led off the fourth with a single to right.
Moments later, Arias threw wildly past Berkman trying to pick off Morgan at first. Morgan nearly circled the bases, but Berkman threw him out at the plate.
Arias walked three and struck out six. He started in place of Brandon Backe, who was scratched because of soreness in his arm during a bullpen session Saturday.
LaTroy Hawkins pitched a scoreless eighth. He has not allowed a run in 16 games since coming to the team in a trade with the New York Yankees on July 30.
Jose Valverde pitched the ninth for his NL-leading 41st save in 47 attempts. He has recorded saves in a club-record 14 consecutive appearances.
Snell (6-11) went six innings, allowing three runs and six hits. He walked three and struck out nine.
"He threw the ball well," Pirates manager John Russell said. "He had one bad stretch, but he gave us a chance. He was aggressive. Hopefully, he can build off of this."
Ryan Doumit and Adam LaRoche hit back-to-back RBI singles for the Pirates in the sixth.