Rollins hit the first of six singles in that ninth inning. Pinch-hitter John Mayberry Jr. hit the last, a line drive to center that brought Ben Francisco home with the winning run.
Instead of a listless loss that would have had them mouthing platitudes - it's just one game, it's a long season - the Phillies had a walk-off win.
"It was exciting," Ryan Howard said. "We just had that feeling that guys were going to come through."
A loss is just one of 162 games. A win like this counts for much more - if not in the standings, then in creating a personality for a team without the departed Jayson Werth and the injured Chase Utley and Brad Lidge.
"We got to start off 1-0 instead of the other way around," Rollins said. "It's one game to build off of. You always hear that it's early in the season, and it is, but it's a lot better to be 1-0, winning the game the way we did, than 0-1."
These Phillies have always maintained a calm confidence in themselves. That has served them well. There is no panic when a key player gets hurt, no worries when a rough spell allows rival teams to gain ground in the standings. Each of the last four seasons has ended with these Phillies on top in the National League East.
But every team is different. Take Werth out of the lineup and out of right field. Put Utley on the disabled list with a worrisome knee injury. Sideline Lidge with a small tear in his right shoulder. Add one year's wear and tear to the bodies of Howard, Rollins, Raul Ibanez, and Carlos Ruiz.
Even with the much hyped collection of ace starting pitchers, there is no telling what impact all that change will have on a team. That's why the keen anticipation of this opening day was alloyed by concerns about the lineup and the defense and the bullpen.
The first eight innings felt like waking from an anxiety dream, only to find that it wasn't a dream at all. The lineup sleepwalked through six innings, making former Phillies ace Brett Myers look like, well, Halladay. Francisco, Werth's replacement in right field, misplayed a fly ball into a two-base error. Middle relievers J.C. Romero and David Herndon turned a taut 1-0 game into a 4-0 Astros lead.
If there was a way to undermine this magnificent rotation, the Phillies had found it. Except that it didn't feel right, letting Halladay's superb six-strikeout performance go to waste. It was this team's first chance to prove it still holds that winning formula.
"That was just desire to win," Rollins said. "Nobody wanted to make that last out. I think everyone personally felt Roy didn't deserve to get a loss after a performance like that."
Rollins and Howard, the team's two MVP award winners, started it off with base hits. But it was Francisco, Werth's replacement, who drove in Rollins to make it 4-3. It was Wilson Valdez, Utley's replacement, who tied the game with a single. It was Mayberry, a player the Phillies hope develops into an important role player, who won it.
The Phillies have changed. Their knack for winning has not.
"We got it done," Howard said. "We kind of have that flair for the dramatic at times. A lot of people on the outside talk about our offense [being down]. I think they forget we had a lot of injuries last year and we still managed to win the most games in the major leagues. I think that speaks volumes for the character and personality of this team. We feel like we're not out of the game until that 27th out is made."
It never did get made Friday afternoon. The most anticipated season in Phillies history began with a walk-off win.
"The best thing is that we won the game," manager Charlie Manuel said. "The next best thing, we've got another game to play tomorrow."
With Cliff Lee on deck, nobody's arguing.
Follow columnist Phil Sheridan on Twitter at twitter.com/SheridanScribe. Read his blog at http:// go.philly.com/philabuster or his recent columns at http://go.philly.com/philsheridan.