About 40 members of Matt Morris’s family showed up at Shea Stadium to watch him pitch yesterday. Sitting in a rented suite, they were among the few fans in the ballpark who enjoyed his performance.

The right-hander from nearby Middletown pitched effectively into the eighth inning and John Mabry homered and drove in three runs to lead the St. Louis Cardinals to a 4-2 victory over the Mets.

Subbing at first base to give All-Star slugger Albert Pujols his first day off this season, Mabry also turned two nifty double plays to snuff out potential rallies.

Reggie Sanders hit his 10th home run for the NL Central-leading Cardinals, who took two of three from the Mets and improved to 12-4 on the road.

Mike Cameron homered, doubled, and scored both runs for the Mets (19-19), who lost for the fifth time in seven games following a four-game winning streak.

“When you don’t score a lot of runs, you can’t blame the pitcher,” manager Willie Randolph said.

Morris (3-0) got Floyd on a popup with runners at the corners to end the sixth and pumped his fist as he walked off the mound. The Cardinals’ starter gave up two runs and six hits in 7 2/3 innings, his longest outing since off-season shoulder surgery.

Jason Isringhausen got three outs for his ninth save in nine chances, and second in two days.

Jim Edmonds drew a leadoff walk from Mets starter Aaron Heilman (3-3) in the second. One out later, Mabry drove a 1-2 pitch over the right-center fence for a 2-0 lead. Sanders followed with a solo shot to center with two outs in the fourth – after Heilman struck out Larry Walker and Edmonds.

Cameron doubled leading off the fourth the Mets’ first hit, then scored on Floyd’s double-play grounder.

Mabry’s two-out RBI single in the sixth made it 4-1.

Cameron connected in the eighth to chase Morris, who struck out six. Heilman allowed four runs and seven hits in 5 2/3 innings, matching a career high with seven strikeouts. The right-hander from Notre Dame could be sent to the bullpen or the minors when lefty Kaz Ishii comes off the disabled list, probably this week.

“I’d rather be a starter. That’s where I’m most comfortable. But I’ve pitched in relief before, and right now I just want to do whatever I can to help the ballclub,” Heilman said.

The Cardinals have won 12 of 15 games against the Mets and are 20-7 against them since 2001.