Roger Clemens's start was his fifth at Wrigley Field. He had three with the Astros last year, going 2-0, and lost an interleague start with the Yankees in 2003, denying him his 300th victory.
Atlanta's Ryan Langerhans's 0-for-20 slump ended with a run-scoring single in the fifth.
Lefthander Tom Glavine, who won 242 games with the Braves, then signed with the Mets as a free agent in 2003, has only one win in nine career starts against Atlanta.
Manager Tony La Russa won his 823d game with the Cardinals, passing Whitey Herzog for second place on the franchise list. La Russa is 218 victories behind franchise leader Red Schoendienst.