Harper's grand slam came in the second inning of the Phillies' 11-1 win on Tuesday at Busch Stadium in St. Louis. It was his first home run since April 26 and his first grand slam since April 19, 2017. Harper's two-hit night also marked his first game with multiple hits since April 19 of this season.
"I think anytime you come in and face anybody, you just try to go in there and have the best game you can," Harper told reporters, according to MLB.com.
"You just try to be a good baseball player and that's about it. You don't really think about who you're facing or anything like that. Just try to go out there and play the best I can."
Harper reached base for the first time in Tuesday's win with a first inning walk from Cardinals starter Dakota Hudson. He returned the plate in the next frame, playing a large role in Philadelphia's six-run second inning.
Odubel Herrera began the inning with a double. He later came in to score on a fielders choice and throwing error by the Cardinals. The Phillies went up 2-0 on another throwing error during the next at-bat. Andrew McCutchen walked in the fifth at-bat of the inning.
Hudson forced Jean Segura to line out for the first out of the frame during the next exchange, before Harper walked up to the plate with the bases loaded.
The Cardinals starter fell behind 2-1 in the count before throwing in an 89.2 mph slider for his fourth offering to Harper. The Phillies star swatted the pitch to right field for a 396 foot bases-clearing blast. Harper's slam had an exit velocity of 102 mph and a launch angle of 26 degrees, according to Statcast.
Harper reached base for a third consecutive time with a leadoff single in the fifth inning. He came around to score that inning on a J.T. Realmuto single. Herrera made the score 8-0 when he grounded into a force out in the at-bat following Realmuto's single.
St. Louis scored its lone run on a solo shot from Matt Wieters in the bottom of the sixth inning.
Harper was retired for the first time with a ground out in the seventh inning, but the Phillies still plated two runs in that frame. Rhys Hoskins plated the Phillies' final run with a solo shot in the top of the ninth inning.
Harper is now hitting .236 with seven home runs and 25 RBIs on the season. Hoskins is raking .302 with 11 bombs and 32 RBIs for Philadelphia.
The Phillies face the Cardinals in the series finale at 1:15 p.m. Wednesday in St. Louis.