He pitched superbly as a starter, got a key hit, made a daring baserunning decision and even came out of the bullpen.
Now the Philadelphia Phillies are counting on him in a must-win spot.
Oswalt gets the ball for Game 6 on Saturday when the Phillies try to even the NL championship series against San Francisco.
He'll be back in a familiar role after an unsuccessful guest appearance as a reliever, and he'll be right at home in a ballpark where he's never lost.
"I try to pitch every game like the last one," Oswalt said Friday. "You never know. You're never guaranteed the next day. So it's going to be no different, trying to attack hitters and make them beat me, not trying to put guys on. No different than any other game. It's a must-win game but I treat every one of them like a must-win."
Oswalt dominated the Giants in Game 2, but took the loss when he entered in the ninth and allowed Juan Uribe's game-ending sacrifice fly in Game 4.
Roy Halladay helped the Phillies avoid elimination with a gutsy effort pitching through a groin pull Thursday night, sending the series back to Philadelphia with the Giants ahead 3-2.
But with Oswalt and Cole Hamels lined up to pitch the next two games, the Phillies are confident.
"We've won three in a row a bunch this year," he said. "No one's panicked yet. I know we've got our backs against the wall. But we feel if we got back here in Philadelphia, we have a real good chance of winning the next two."
Oswalt, who was MVP of the 2005 NLCS with Houston, will do whatever it takes to win. The three-time All-Star right-hander pitched in relief on two days' rest Wednesday night. He allowed a pair of singles before Uribe's one-out fly to left gave the Giants a 6-5 win.
"Numbers, to me, are no big deal," Oswalt said. "I didn't want to get the loss for sure. But you never know when you're going to get back here. So that's one of the reasons I wanted to be in the game the other night. I don't know how much longer I'm going to play. But I may not get to this spot again. So I'm going to try to do everything possible to get to that final game."
Jonathan Sanchez, the Game 2 loser, takes the mound for San Francisco. The Giants are looking for their first pennant since Barry Bonds led them to within six outs of the World Series title in 2002.
Sanchez gave up three runs - two earned - and five hits in six-plus innings last Sunday night. The tough lefty had dominated the Phillies in his five previous starts against them, not allowing more than four hits in any outing.
Sanchez beat San Diego on the final day of the regular season to lead San Francisco to the NL West title. He'd like one more clinching victory.
"It's going to be great to get to the World Series," Sanchez said. "Never been there. We've got a lot of guys on the team that have never been there, and to be able to do that, it's going to be something special for me."
After Tim Lincecum outdueled Halladay in the opener, Oswalt threw eight outstanding innings in a 6-1 win in Game 2. He's 10-0 lifetime at Citizens Bank Park, including 6-0 this season.
"I want this guy pitching at home," Phillies manager Charlie Manuel said. "He definitely is a competitor. You can tell that by how he gets the ball and throws it and some of the things he does, how he looks on the mound and everything. Presence counts. What you give off to the hitter and everything definitely counts a lot."
This will be Oswalt's sixth start this year against the Giants, who beat him three times during the regular season when he was with Houston. Oswalt pitched well in those games, but got no run support. He's beaten San Francisco twice since joining the Phillies.
Acquired from Houston on July 29, Oswalt went 7-1 with a 1.74 ERA in 13 games with the Phillies. Oswalt - not Halladay or Cole Hamels - was Philadelphia's best pitcher down the stretch. He was 7-0 with a 1.17 ERA in his last 10 starts.
The two-time NL champion Phillies are trying to force the first Game 7 in franchise history. In 1980, Mike Schmidt and Pete Rose led Philadelphia past Nolan Ryan and the Houston Astros in Game 5 when the NLCS was a best-of-five series.
Hamels, the 2008 World Series MVP, is scheduled to start against Matt Cain on Sunday night if the Phillies survive their second straight do-or-die game. Hamels could even get the call at some point Saturday instead.
"Depends on where we're at in the situation," Manuel said. "Do I want to? No. More than likely I won't, but at the same time, I'm not ruling it out."
Neither team worked out Friday. The Phillies flew home after extending the series Thursday night. The Giants made the cross-country trip on Friday, and their flight got delayed before taking off because President Barack Obama and Air Force One were arriving in San Francisco.
"We've been tested all year. You go back to early August, we've been playing big games," Giants manager Bruce Bochy said. "But these guys, they've been battle-tested. And we know we're playing a club that's loaded with experience, and they are, too. But I like the way my team has handled everything thrown at them and they'll go out there and give it their all. And that's all you can ask."