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The Houston Astros' 4,000th regular-season win in franchise history came in their American League debut.

Rick Ankiel hit a three-run homer and the Astros beat the Texas Rangers, 8-2, to kick off the 2013 MLB season on Sunday night.

Houston, led by rookie manager Bo Porter, had played its first 51 seasons (1962-2012) in the National League. The last time a team swapped leagues and divisions came back in 1998, when the Milwaukee Brewers left the AL Central for its similarly named NL counterpart.

Justin Maxwell went 2-for-3 with two RBI and two runs scored for the Astros, who capped their National League run a year ago with a second straight 100- plus loss season. Jose Altuve and Matt Dominguez each had an RBI for the victors.

Houston starter Bud Norris (1-0) gave up two runs on five hits over 5 2/3 innings to pick up the win. The right-hander went 7-13 with a 4.65 ERA last season.

"To sit at 1-0 right now feels pretty darn good, and we've just got to go back out there on Tuesday and play some more baseball," Norris said.

Erik Bedard gave up just one hit over 3 1/3 innings to record his first career save.

David Murphy and Nelson Cruz each had an RBI for the Rangers, who went 93-69 last season before falling to the Baltimore Orioles in the one-game wild card playoff.

Matt Harrison (0-1) allowed six runs -- five earned -- on six hits and fanned nine over 5 2/3 innings to take the loss. Harrison enjoyed a breakout 2012 season, going 18-11 with a 3.29 ERA.

Texas lost Josh Hamilton, Mike Napoli and Michael Young via free agency, but picked up veterans like Lance Berkman and A.J. Pierzynski. Berkman, of course, spent the first 11 1/2 years of his career with the Astros.

"This is the major leagues, and any team is capable of beating any other team on a given night," Berkman said.

The Astros scored a pair of runs in the fourth. Brett Wallace hit a one-out single to center, moved to second on Carlos Pena's single to left-center field and scored on Maxwell's triple off the top of the left-field wall.

Houston tacked on two more runs during its next at-bat. With Brandon Barnes on first, Ronny Cedeno hit a single to right. Cruz's fielding error allowed Barnes to score and Cedeno to make it to third. Altuve followed with an RBI single to right-center field, making it 4-0.

Texas got two runs back in the sixth. Ian Kinsler and Lance Berkman singled to put runners on the corners. Adrian Beltre lined out to Norris for the second out. Murphy and Cruz followed with consecutive RBI singles. Bedard took over for Norris and retired A.J. Pierzynski to keep it 4-2.

But the Astros gained some breathing room in the bottom half on Ankiel's three-run homer. Maxwell and Dominguez walked to put runners on first and second with two outs. Derek Lowe came in from the bullpen and pinch-hitter Ankiel greeted him with a blast to right, making it 7-2. It was Ankiel's first at-bat in an Astros uniform.

Dominguez's RBI single in the eighth made it 8-2.

Game Notes

These teams have a day off Monday before resuming the series on Tuesday ... The Astros, who earned their first Opening Day victory since 2006, improved to 24-28 all-time in season openers ... Texas fell to 21-21 overall on Opening Day ... Porter is the youngest manager in baseball at 40 years old ... NFL Defensive Player of the Year J.J. Watt of the Houston Texans threw out the first pitch ... Berkman had two hits ... Maxwell had two triples.