Adrian Gonzalez hit a grand slam and Howie Kendrick added a two-run homer as the Los Angeles Dodgers exploded for nine runs in the first two innings off rookie Mike Mayers.
The Cardinals closed the gap, but lost 9-6.
Mayers lasted 1 1/3 innings and became the first pitcher to allow nine or more runs with fewer than two innings pitched in his debut since at least 1913.
With two losses in a row, the Cardinals dropped back to 7.5 games behind the Cubs in the Central Division and are just a game ahead of Pittsburgh who has won two straight.
Five teams are bunched in the Wild Card race with the Dodgers leading the Marlins by two games and Miami leading the Mets by 1/2 game, the Cardinals by one and the Pirates by two for the second WC spot.
The 24 year old Mayers was the Cardinals 3rd round draft pick (93rd overall) in 2013 out of the University of Mississippi. He has 64 minor league starts, posting a 19-24 record with a 3.49 ERA over 350.2 innings pitched and 273 strikeouts.
His 2016 season has been split between Springfield (AA) and Memphis (AAA) with nine starts at each level, posting a combined record of 10-6 with a 2.62 ERA in 106.2 innings pitched.
Mayers was the first pitcher to make a start for the Cardinals this season who was not a part of the team’s starting five from the Opening Day roster.