The stakes will be much higher when the All-Stars go head-to-head on a mound for the first time Friday night.
It'll be Halladay vs. Carpenter in Game 5 with a berth in the NL championship series on the line for the Philadelphia Phillies and St. Louis Cardinals.
"You definitely look forward to it," Halladay said Thursday. "Not only is Chris a good pitcher, but obviously a good friend. We've talked about this scenario. I think it's something we're both looking forward to. It's going to be a challenge.
"Going in, you know what you're up against, you know how good they are, you know how good Chris is. We haven't got a chance to pitch against each other, and if you're going to do it for the first time, might as well be now," he said.
The best buddies already have made offseason plans for a fishing trip. One of them will get a head start on his vacation.
"It's been a pretty good friendship for a long time," Carpenter said. "We've pitched together, we've vacationed together, we communicate a bunch during the offseason and during the season. He just invited me to go fishing this winter, so I mean, we've got a real good relationship. It's going to be a lot of fun."
This is a "dream matchup," according to Cardinals manager Tony La Russa, who set it up by pitching Carpenter on three days' rest for the first time in his career in Game 2.
"They've got so much common history and they're both great pitchers, great competitors, and now we're going to do it," La Russa said. "It's going to be as good as it gets. We're looking forward to being there and trying our best. And they are so close, they both have a lot of weapons. You can see each of those guys four times and they'll give you something different all four times. Halladay is every bit as good as his record and his awards and all that, but Carp is in that same category."
The Phillies, heavy favorites entering the division series, are counting on the ace of their star-studded rotation to outduel his pal and put away those pesky Cardinals.
The pressure will be on Halladay, though he downplays it. Nothing less than a World Series title will satisfy anyone in Philadelphia. Those franchise-record 102 regular-season wins won't mean a thing if the Phillies don't advance.
"I don't think you can get too caught up in what game it is, and what it means," Halladay said. "I think if you go out thinking: 'Wow, this is everything, all-in-one,' I think it can make too much out of it."
Halladay beat the Cardinals in the opener, despite a shaky start. He allowed a three-run homer to Lance Berkman in the first inning, but dominated the rest of the way. Halladay retired the last 21 batters he faced, and turned an eight-run lead over to the bullpen in an 11-6 win. He allowed three runs and three hits, striking out eight in eight innings.
Carpenter struggled in his start, allowing four runs and five hits in three innings in his shortest outing of the season. But the Cardinals overcame a 4-0 deficit against Cliff Lee and beat the Phillies 5-4 to even the series.
"Carp is all about winning, bottom line," said third baseman David Freese, who had four RBIs on a homer and double in Game 4. "That's what he said after his outing. We fought back, and that's what Carp wants, he wants to win. And he wants that ball, Game 5, and he's going to be ready. He knows what we're going up against in Philly with Halladay and their offense, but I think that they understand that we're going to bring our A game. And it's going to be exciting. It's going to be a lot of fun, and we'll see what happens."
There are so many similarities between Halladay and Carpenter - right down to even their height and weight. Both are listed at 6-foot-6 and 230 pounds.
The 36-year-old Carpenter, the 15th pick in the 1992 amateur draft, is a three-time All-Star and the 2005 NL Cy Young Award winner. He's 144-92 in 14 seasons with the Blue Jays and Cardinals.
The 34-year-old Halladay, the 17th pick in the 1995 amateur draft, is an eight-time All-Star and he's won the Cy Young Award once in each league. He's 188-92 in 14 seasons with the Blue Jays and Phillies.
Halladay has more individual accomplishments and extra hardware on his trophy case. But Carpenter has something Halladay desperately wants: a World Series ring. Carpenter helped the Cardinals beat Detroit in the 2006 World Series.
"We feel confident with the guys that we have in our clubhouse, and we get to play the deciding game in front of our fans," Halladay said. "We all feel like this is something we can accomplish, and we know it's going to be a challenge, but I think we're all looking forward to it."
Carpenter had limited success with the Blue Jays, never winning more than 12 games in six years in Toronto. He was released after the 2002 season, and signed with the Cardinals two months later. His career really took off in St. Louis, though he's missed nearly three full seasons because of arm problems.
Halladay already was widely considered the best pitcher in the game when he joined the Phillies last year. He lived up to enormous expectations in his first season in Philadelphia, pitching a perfect game in the regular season, a no-hitter in his first postseason start and winning the Cy Young Award.
All those nights they stayed up late on the road, sitting in hotel rooms and talking about how to become better pitchers, surely worked out for both of them.
"I really felt like we grew together," Halladay said. "Coming up, we both kind of struggled with, we were supposed to come in and lead this team and be these great pitchers right out of the gate, and I think it was tough for both of us not really knowing how to go about that. But I really did feel like we kind of learned together, more mentally how to approach the game and how to play the game, and it was a lot of fun.
"It was just a great experience to go through that together, to learn together, to get better together, and ultimately coming out of there feeling like the time that we spent had really benefited both of us."
Both pitchers credit their friendship for helping them reach this point.
"We went through a lot of the same issues at the same time," Carpenter said. "A lot of it was mental. We both knew that we had quality stuff. But mentally as young kids with high expectations on you, this game is hard, and if you can't control that stuff in your mind and the game goes a thousand miles an hour, you're going to have a hard time executing, and fortunately we were able to figure it out."
The Cards are playing with house money. They wouldn't even be here without help from the Phillies. St. Louis trailed the Braves by 10½ games on Aug. 25, but went 23-8 the rest of the way and earned a wild-card berth after Game 162 when Philadelphia completed a three-game sweep in Atlanta.
They haven't played like an underdog in this series, and they won't be happy simply pushing the Phillies to the limit.
"We haven't done anything yet," slugger Albert Pujols said. "We just tied the series."