Kolten Wong belted a solo home run with two outs in the ninth inning as host St. Louis beat Pittsburgh with a walk-off blast for the second straight night.
Ernesto Frieri (1-4) replaced Tony Watson to start the frame and retired the first two batters before Wong lined a 3-2 offering over the wall in right field for his third homer of the season. Wong finished with two hits and three RBIs, Matt Holliday drove in a pair of runs and Trevor Rosenthal (1-4) notched the win by tossing a scoreless top of the ninth.
Pedro Alvarez and Andrew McCutchen each hit a two-run homer for the Pirates, who have lost the first two contests of the four-game series after Matt Adams hit a two-out homer in the ninth Monday. Rookie Gregory Polanco collected three hits and scored a run while also recording his fifth stolen base.
Wong gave the Cardinals the lead in the second inning with a two-run double, but Pittsburgh pulled even on Alvarez's 14th blast in the fourth. McCutchen put the Pirates in front with his 14th of the season in the fifth before Holliday delivered a two-run double in the bottom of the inning to again knot the contest.
Neither starter was particularly effective in the battle between the National League Central rivals. Pittsburgh's Vance Worley yielded four runs and nine hits over five innings while St. Louis' Carlos Martinez was tagged for four runs and eight hits in six frames.
GAME NOTEBOOK: St. Louis RHP Pat Neshek extended his scoreless innings streak to 11 2/3 by working a perfect eighth.
Pittsburgh LHP Francisco Liriano (oblique) is expected to be activated from the disabled list and start against Cincinnati over the weekend.
Cardinals LHP Jaime Garcia is scheduled to undergo season-ending surgery to address symptoms related to thoracic outlet syndrome on Friday.