Suppan, one of three starters St. Louis did not sign after winning their first title in 24 years, pitched 6 1/3 solid innings in a 3-2 Milwaukee Brewers victory.
He beat Kip Wells, who essentially replaced him in the Cardinals rotation.
"Surprisingly, I felt actually OK," Suppan said. "The first day coming in was a little odd for me, but going out there I was just getting ready for a game.
"I think on the field I was just focused on hitting my spots."
Rickie Weeks hit a tiebreaking two-run homer in the fifth inning for Milwaukee, who snapped the Cardinals' four-game winning streak.
The game was originally scheduled to start in the afternoon but the Cardinals decided Friday to push it back six hours to avoid a second straight rainout. It was 41 degrees when it started and a crowd of 42,805 was announced, keeping alive the team's solid slate of sellouts at year-old Busch Stadium, although there was more than 13,000 no-shows.
Suppan was allowed to leave for a four-year, $42 million deal in Milwaukee after winning the NL Championship Series MVP last fall and totaling 44 victories over three seasons. Wells joined the Cardinals, signing a one-year, $4 million deal coming off an injury-plagued 2006.
Suppan allowed two runs on five hits, a day after his first visit to Busch Stadium since the World Series parade and two nights after he and his wife dined at Scott Rolen's home. He struck out five, walked none and scored the game's first run after drawing a walk with one out in the third.
Suppan has won his last four decisions at Busch Stadium spanning seven starts.
"He did what he always does, he goes out there and throws a lot of strikes, tries to pitch off the corners and tries to change things up," said the Cardinals' David Eckstein, who was 0-for-3 against Suppan. "Anybody who knows Soup, he did that for us all last year."
The Cardinals are 0-4 at home since beating the Tigers in Game 5 of the World Series, including a season-opening three-game sweep to the Mets in which they were outscored 20-2. Wells allowed three runs in seven innings for St. Louis, which got an RBI from Rolen and Aaron Miles.
"I'm not worried about the offense," Miles said. "It's not going to be too long before this team starts scoring some monster runs like it usually does."
Milwaukee has won three straight on the road, equaling its best run all of last season, and is 3-1 with three games left in a seven-game trip. The Brewers were 27-54 on the road last year, second worst in the National League, with no winning trips of more than three games.
Manager Ned Yost said a homecoming game shouldn't be too difficult for Suppan to deal with.
"This guy pitched Game 7 of the NLCS, that's where the pressure is," Yost said. "This is nothing. I think it makes for a good story, but I don't think it matters to Jeff who he's pitching against."
The Brewers loaded the bases against Wells (1-2) on Weeks' infield hit and a walk to J.J. Hardy in the inning before Suppan, who drew chants of "Soup! Soup!" before his at-bats, scored on Prince Fielder's sacrifice fly.
"I did hear a few," Suppan said. "That's always nice."
The Cardinals tied it in the fourth on a leadoff double by Chris Duncan and Rolen's one-out single, which snapped a 3-for-18 slump. Rolen missed the previous two games with upper back spasms.
Weeks' third homer, and second in two games, put the Brewers ahead 3-1 in the fifth.
Three Brewers pitchers recorded an out apiece to escape the seventh when the Cardinals scored one run and left the bases loaded. Miles' pinch-hit single cut the deficit to one and Eckstein walked before Duncan, who had two hits, fouled out against Greg Aquino to end the inning.
Francisco Cordero worked the ninth for his fourth save in four chances.
- Rolen and Albert Pujols received Gold Gloves before the game, and Chris Carpenter (Pitcher of Year) and Pujols (Man of the Year) received Player's Choice Awards.
- All the Cardinals and Brewers will be wearing No. 42 on Sunday on the 60th anniversary of Jackie Robinson's major league debut.
- Fielder was 0-for-3 with a sacrifice fly and two strikeouts, going hitless for the first time this season. He had hit in 10 straight overall, going 14-for-43 (.326), counting a two-hit game in the 2006 finale against the Cardinals.