Each time the Washington Capitals have crept close to the .500 mark, they played as if winning as many games as they lose requires some great bodily sacrifice; as if reaching that modest plateau might spread a nasty rash around the dressing room or poison the lavish postgame buffet.

Tonight, it appeared they might have the same reaction after a brutal first period, but instead battled back from 2-0 and 3-2 deficits against the New York Islanders for a wild 4-3 win at Nassau Coliseum. The Capitals (9-9-4) reached .500 for the first time since the fifth game of the season after blowing opportunities to do so three times--losing a two-goal third period lead to Phoenix to tie, 2-2; allowing three straight third period goals to Los Angeles, 5-2; and getting pounded last week by Buffalo, 5-2.

"It's a big psychological hurdle," said Coach Ron Wilson, who won his 200th game. "It's so hard to get to. When you're below .500 it's hard to get to it. It can keep you down or it can push you up, and now we're right on the line. When we were four or five games down, it looked a long way off. We're feeling a little better about ourselves now."

The Capitals, 7-3-2 this month, entered the third period tonight down 3-2, but Peter Bondra's blistering slap shot on the power play--a sequence that appeared to be offside--tore past Felix Potvin's glove five minutes into the period. He wasn't done. The Capitals mounted a flurry with six minutes left, keeping the puck in the zone, and Bondra (13 goals) found a crease in the defense. Sergei Gonchar fed him a few feet from the goal and he roofed the shot, giving Washington a 4-3 lead. It erased an awful start and was another spunky effort from a team that already has two wins and two ties this season when trailing after two periods (1-34-2 last season).

"We started sloppy but we kept working hard," Bondra said. "We got better and better and by the end we were creating a lot of chances."

Backup goalie Craig Billington (34 saves) was tested more in the first five minutes tonight than he was in all of Friday's shutout of Nashville. The Islanders, playing their first home game in two weeks, jumped on Washington from the opening faceoff. The Capitals could not complete a simple pass. An elite faceoff team struggled to win a draw in its own zone. Eighteen-year-old rookie Tim Connelly won a key draw, and pushed a meek shot to goal. Capitals center Jan Bulis, back from a rib muscle injury, accidentally tipped it between Billington's pads four minutes into the game. Billington's shutout streak ended at 139 minutes.

One shot and 14 seconds later the red light was glaring again. The Capitals turned the puck over off the ensuing faceoff--a weak dump-in was picked off--and tough guy Gino Odjick completed a two-on-one, which also looked offside. Billington (101 saves on 106 shots in four starts) had no chance.

Friday, the Capitals set season highs for most shots in a game and a period against Nashville. Tonight, the Islanders, a team tied with expansion Atlanta for the worst record in hockey--the lowest-scoring team in the league--produced 19 shots in the first period, the most Washington has allowed in a period this season. Fifteen Islanders put at least one shot on goal in the first period; Nashville managed 17 shots in the entire game.

One sequence salvaged the period. Richard Zednik pried a puck loose at the boards, and Steve Konowalchuk beat Potvin with a deadly shot with three seconds left in the period, snapping his nine-game funk. The Capitals' bench erupted--13 sticks pounded the boards in unison; Islanders Coach Butch Goring hung his head in disgust.

"We kind of got lucky tonight," Wilson said. "They had us in a position and let us off the floor.

That wasn't nearly as deflating as what transpired two minutes into the second period. James Black fired a casual wrist shot as he crossed the blue line, merely looking to end his shift, and Potvin misplayed the puck badly. Suddenly, the game was tied. The Capitals produced the first nine shots of the period.

The Islanders did not challenge Billington again until the game's midpoint. But that was enough to take the lead. Josh Green carried the puck up ice and Mathieu Biron found Mariusz Czerkawski alone in front. Czerkawski's spinning shot made it 3-2. He nearly put the game away short-handed a few minutes later, but Billington made two crucial saves on blistering slap shots and stopped his short-handed breakaway a minute into the third period and power-play breakaway late in the final period.

Capitals Notes: Forward Chris Simon left the game in the second period with a neck sprain but is expected to play Monday. Defenseman Jamie Huscroft replaced Brendan Witt, who was a late scratch with a muscle strain. Witt is listed as day-to-day. Defenseman Joe Reekie (bruised foot) was placed on injured reserve; RW Joe Sacco (bruised leg) and C Mike Eagles (healthy scratch) also did not play. . . . Washington has killed off 70 of 72 power plays over the last 17 games. . . . Defenseman Calle Johansson picked up his 400th point as a Capital. . . . Center Adam Oates has 13 points in the past 12 games. . . . Washington is 4-0-2 in back-to-back games.

CAPTION: Capitals' Craig Billington covers the puck to keep it from Islanders' Olli Jokinen, left, as Sergei Gonchar looks on.