Terry Cummings scored 23 points and Paul Pressey 22 and each made a key play down the stretch as the Milwaukee Bucks rallied from an 18-point halftime deficit to beat the New Jersey Nets, 118-113, and complete a three-game sweep of their NBA playoff series last night in East Rutherford, N.J.

The Bucks, who allowed the Nets 73 points in the first half, held New Jersey to 40 in the last two periods. Milwaukee had to play the last 14 minutes without all-star guard Sidney Moncrief, who strained his left foot.

The Bucks will play the winner of the Washington-Philadelphia series in the second round of the playoffs.

The Bucks wiped out most of the 73-55 halftime deficit by outscoring the Nets by 36-22 in the third period, drawing to 95-91 going into the final 12 minutes.

The Bucks got as close as one point on six occasions in the fourth period before Pressey stole a pass from New Jersey's Otis Birdsong, drove for a layup and, after drawing a foul, sank the free throw for a 112-110 lead with 2:28 left.

After the Nets tied the score, Cummings gave Milwaukee the lead for good on a base-line jumper with 52 seconds left. The Nets missed three of four foul shots in the final minute, ruining any chance for a comeback.

Birdsong paced the Nets with 28 points and Buck Williams had 25.

Pistons 106, Hawks 97: In Pontiac, Mich., Isiah Thomas (20 points) made a basket and two free throws early in the fourth quarter to turn back an Atlanta comeback, keeping Detroit alive in the playoffs. Atlanta still leads the best-of-five series, two games to one, with Game 4 Friday night in the Pontiac Silverdome.

Atlanta, trailing by 84-68, scored the first seven points of the final period to make it 84-75 with 9:33 left. But Thomas, playing with an ulcerated bladder, scored from near the top of the key at 8:36 for the Pistons' first points of the quarter and made two foul shots 24 seconds later to restore his team's lead at 88-75.

Kelly Tripucka led Detroit with 33 points and combined with Earl Cureton to hold Dominique Wilkins to 21 points after the Atlanta star ripped the Pistons for 50 in Game 2. Wilkins did not score in the fourth quarter until 3:49 remained.

Nuggets 115, Trail Blazers 104: In Portland, Ore., rookie Blair Rasmussen scored 26 points, including a crucial three-point play late in the fourth quarter, to lift Denver to victory. The Nuggets lead the best-of-five series, two games to one, with Game 4 in Portland Thursday.

Rasmussen, a 7-footer who averaged three points per game in the regular season, topped his previous high game by 11 points. He also had nine rebounds.

Denver led most of the rest of the game, but reserves Jim Paxson and Terry Porter triggered a fourth-quarter Portland rally that caught the Nuggets at 91-91 with five minutes left. Rasmussen then sank a 12-footer and was fouled. His free throw put Denver on top for good at 94-91 with 4:34 to play.

Rockets 113, Kings 98: Ralph Sampson and Lewis Lloyd scored 25 points each, leading visiting Houston to a three-game sweep of its playoff series with Sacramento. The Kings' Eddie Johnson had 33 points.

Lloyd's 10-foot jumper with 10:30 left in the first half gave Houston a 29-28 lead, and the Rockets never trailed again.

Houston led by 55-51 at halftime, and Lloyd's three-point basket with two seconds left in the third quarter gave the Rockets an 87-73 lead.