Mesoraco went deep for the fourth straight game, driving a 1-0 pitch from Hector Rondon (1-2) into the basket in left-center for his 13th homer. It was Mesoraco's second grand slam of the season and No. 3 of his career.
Billy Hamilton had a tiebreaking RBI single earlier in the inning as Cincinnati won for the sixth time in seven games to move above .500 for the first time this season at 38-37. The winning sequence started when Chris Heisey reached on a pinch-hit single with two outs and no one on base, snapping an 0-for-16 rut.
It was the first homer allowed by Rondon since last Aug. 3.