PITTSBURGH (AP) _ Attendance was just 9,044 in Three Rivers Stadium Monday night and that made a bad game worse for Pittsburgh Pirates starter Dave LaPoint.

''You could really hear the crack of the bat,'' LaPoint said after he was one of four pitchers pounded for 15 hits in the Pirates' 7-1 loss to the St. Louis Cardinals.

Willie McGee had four hits, the Cardinals had a season-high seven doubles and Jose DeLeon won for the seventh time in the last eight decisions.

Because the Pirates used four left-handers, the switch-hitting McGee took his first right-handed swings in a month. He has been bothered by a strained muscle in his side and Manager Whitey Herzog only used him against right- handed pitching.

''I took my first round of batting practice and came in for treatment and it dind't feel too good,'' McGee said. ''But I got comfortable after that and I put it out of my mind.''

The Cardinals are last in the National League in doubles and Herzog knows why.

''We don't hit the ball hard enough,'' he said.

DeLeon, 13-9, allowed three hits, struck out five and walked four in his third complete game. He is 7-1 with four no-decisions since July 29, losing only to the Pirates last Wednesday in St. Louis.

McGee and Ozzie Smith started the game against LaPoint, 4-2, with singles and both scored when Pedro Guerrero doubled to left.

Tony Pena and Guerrero each had three hits.

In the second, Tom Pagnozzi singled, Tom Lawless walked and both advanced on DeLeon's bunt. McGee hit a run-scoring single and Smith added a sacrifice fly for his 500th career RBI.

In the seventh, McGee doubled and scored on Pena's single. McGee added an RBI double in the eighth and Tom Brunansky had an RBI double in the ninth.

With two outs in the Pirates sixth, Ken Oberkfell singled, Andy Van Slyke walked and Bobby Bonilla hit an RBI single.