On August 10, 1985, Willie McGee picked up 7 hits in 10 at bats in a doubleheader sweep of the Phillies at Veterans Stadium in Philadelphia. The Cardinals won the first contest 5-4, McGee went 3 for 5 with two runs scored and a ribbie in the contest and he was just getting started. In the second tilt, McGee went 4 for 5, he knocked a 3 run shot out of the yard in the second inning and finished the game with 4 rbi's. McGee was the hottest hitter in the National League up to that point, he was hitting .351 at the end of that day and he didn't cool off as he was on the way to winning the National League's MVP award. He finished the season leading the league with 216 hits, 18 triples, and a .353 average that gave him the first batting title of his career.
Here are the box scores for both games
Game 1: http://www.baseball-reference.com/boxes/PHI/PHI198508101.shtml
Game 2: http://www.baseball-reference.com/boxes/PHI/PHI198508102.shtml