PHILADELPHIA - The Phillies began one of the most anticipated seasons in club history with a dramatic victory Friday afternoon.

Pinch hitter John Mayberry Jr. knocked in the winning run with an RBI single as Philadelphia scored three runs in the bottom of the ninth to beat the Houston Astros 5-4 before 45,237 raucous fans at Citizens Bank Park.

The Phillies trailed 4-0 as the bottom of the seventh began and 4-2 when they came to bat in the bottom of the ninth.

Jimmy Rollins and Ryan Howard began the ninth with singles. Ben Francisco scored Rollins with a one-out single to the cut the Astros lead to a run.

Carlos Ruiz followed with a single to load the bases. Wilson Valdez then singled to left to score Howard and tie the game.

Mayberry lined a 2-2 pitch over Astros center fielder Michael Bourne's head to score Francisco with the winning run.

Phillies starting pitcher Roy Halladay allowed one run in six innings.

Friday began one of the most hyped seasons in Phillies history. Much of that excitement is built around the team's starting pitching staff of Halladay, Cliff Lee, Roy Oswalt, Cole Hamels and Joe Blanton. Anything less than World Series appearance and many fans will deem the season a disappointment.

The game was played in dry but chilly and windy conditions.

The temperature when Halladay threw the first pitch - a 92 mph fastball for a strike - at 1:11 p.m. at 41 degrees.

The Astros took a 1-0 lead in the top of the sixth inning. Angel Sanchez led off with a single and went to third on Hunter Pence's double. Sanchez scored on Bill Hall's one-out RBI groundout.

Halladay threw six innings and allowed five hits. He struck out six, walked none and threw 101 pitches.

Houston took a 4-0 lead with three runs in the top of the seventh. Astros outfielder Michael Bourne, who played with the Phillies in 2006-07, knocked in two runs with a triple to deep center fielder.

The Phillies managed just two hits off Houston starter Brett Myers in the first six innings. Myers, who pitched for Philadelphia from 2002-09, dispatched the Phillies with ease. He needed just 46 pitches to get through the first five innings.

The Phillies offense finally scored in the bottom of the seventh. Howard and Ibanez knocked in runs with a sacrifice fly and an RBI groundout, respectively.

After the Phillies ninth-inning rally, Philaadelphia fans can't take a break.

Lee makes his 2011 debut at 7:05 p.m. Saturday.