ST. LOUIS -- So much for St. Louis' plan of getting well this weekend against the Chicago Cubs.
Scoring three two-out runs against Trevor Rosenthal with two outs in the top of the eighth inning Saturday night, Chicago rallied for a 6-5 win, its second straight over the slumping Cardinals.
Rosenthal (1-3) entered the game with a 2.17 earned run average and a 77-12 strikeout-walk ratio in 54 innings, but made things tough on himself right away by issuing free passes to Welington Castillo and Nate Schierholtz.
After Starlin Castro and Cody Ransom fanned, Darwin Barney ripped a 3-2 pitch to right-center for a game-tying double. Pinch-hitter Dioner Navarro followed with a tie-breaking double.
Schierholtz tacked on insurance with an RBI single in the ninth off Michael Blazek as the Cubs (52-64) won for just the fourth time in 13 games.
Blake Parker (1-1) worked a scoreless seventh inning for his first big league win. Kevin Gregg yielded Matt Holliday's second homer of the game in the ninth but picked up his 25th save.
St. Louis (66-50) fell to 1-5 on its 10-game homestand and 4-13 in its last 17 games. It now trails National League Central leader Pittsburgh by 4 1/2 games, pending the result of the Pirates' rain-delayed game in Colorado.
Busch Stadium has allowed the second-fewest number of home runs, with only Miami's Marlins Park more favorable to pitchers. But it played against tendency early in this one.
Chicago grabbed a 1-0 lead in the top of the second when Welington Castillo led off with his fourth homer of the year, into the Cubs' bullpen. It came on a 2-0 pitch from Michael Wacha, who was recalled from Triple-A Memphis to make his first big league start since June 11.
After facing the minimum through three innings, Chicago's Carlos Villanueva ran into trouble in the fourth. With Matt Carpenter and Carlos Beltran aboard after singles, Holliday lined a three-run shot to left, his 14th of the season and first since July 9.
Castillo drew the Cubs within a run in the fifth with a sacrifice fly.
NOTES: The Cubs selected the contract of OF Darnell McDonald from Triple-A Iowa and sent down C J.C. Boscan. The 34-year old McDonald played a combined 42 games last year with the New York Yankees and Boston Red Sox, hitting .205. ... The Cubs regained the services of Navarro (right ankle sprain), who was injured Wednesday night in Philadelphia in a home plate collision with Chase Utley. ... St. Louis sent RHP Carlos Martinez to Memphis for a Saturday night start. Martinez started for the Cardinals and lost Thursday night's game with the Los Angeles Dodgers, leaving in the fifth inning because of cramping.