AUBURN HILLS – Prevent the surf from reaching the shore with a sponge. Stop the 8:15 out of Grand Central with a piece of twine. And then try the really tough task – keep Detroit’s Ben Wallace off the glass.

That was Net center Jason Collins’ task as the Nets started the Eastern Conference semis against the Pistons last night.

“Definitely, I’ve got to keep him off the offensive glass. He’s one of the best rebounders in the league,” said Collins, who was paired against the NBA’s second best offensive rebounder and third best overall board man.

Collins discovered, to his chagrin, just how nasty an assignment Big Ben can be because before Game 1 was even two minutes old, Collins was on the bench saddled with two fouls – and he played just two minutes in the entire half.

Wallace, meanwhile, was establishing the foundation of his 13-point, 11-rebound evening. In the first quarter alone, Wallace snared six rebounds as the Piston held an embarrassing 14-2 rebound lead. Ben was big in every sense. Wallace, at 6-9, 240, is a fearsome specimen. In last year’s playoffs, Wallace gobbled up the Nets for 17.3 rebounds a game.

“It’s positioning, his athleticism. It’s a lot of things,” Collins said. “It’s a team effort. But I know I have to definitely keep it in mind to find him as early as possible and keep him away from the basket.”

While the Nets figured to look to Collins in the series for some of his little face-up jumpers in an attempt to lure Wallace away from the lane, it was Detroit’s man in the middle who tried becoming a jump shooter early. Wallace bagged a turnaround jumper at 5:36 of the first quarter amid a stout Nets defense. Wallace’s next two shots also were jumpers.