Pittsburgh, PA (SportsNetwork.com) - Tony Sanchez's RBI double in the seventh inning proved to be the difference as the Pittsburgh Pirates edged the St. Louis Cardinals, 2-1, in the rubber match of a three-game set at PNC Park.

With the score knotted at 1-1, Pedro Alvarez worked a leadoff walk. Adam Wainwright fanned the next two batters, but Sanchez hammered a double to right-center to score Alvarez all the way from first.

Mark Melancon worked a perfect eighth and Jason Grilli spun a scoreless ninth to earn his first save of the season.

Neil Walker also had an RBI double for the Pirates, who start a nine-game road trip on Tuesday against the Cubs.

Edinson Volquez allowed just one run on three hits and one walk while fanning four over 5 2/3 innings. Tony Watson (1-0) worked 1 1/3 perfect innings in relief to earn the win.

Jon Jay stroked an RBI triple for the Cardinals, who fell to 3-3 on the season.

Wainwright (1-1) allowed both runs on five hits while striking out seven over seven innings to absorb the loss.

Pittsburgh broke through in the fourth when Walker laced an RBI double to right field. Andrew McCutchen reached on a one-out double to right and came around to score easily when Walker smacked a double that bounced off the wall.

The Cardinals were unable to get a baserunner past first through the first five innings, but finally got on the board in the sixth on Jay's run-producing triple.