Pirates first baseman John Jaso's third homer of the season traveled 371 feet and gave the Pirates a 3-1 lead in the fifth inning.
Jaso's shot over the right field wall came on a full-count changeup from Cardinals starter Michael Wacha. It scored Chris Stewart, whose RBI double made Wacha's only walk of the game hurt.
Stewart skipped his grounder down the third-base line to tie the game 1-1. It rolled to the wall and gave Jordy Mercer, who walked, plenty of time to go from first to home.
Suddenly, Wacha has gone from looking solid to shaky.