The Washington Capitals' nine-year wait to clinch a playoff berth has been prolonged at least one more night. Wayne Gretzky scored two goals and set up a third tonight to carry the Edmonton Oilers to a 6-3 triumph at Northlands Coliseum.

The Capitals need a victory Thursday night at Calgary or a loss by the New Jersey Devils against Detroit--or ties in both games--to assure that first playoff competition.

Although outshot, 32-30, the Oilers were able to break open the game in circumstances familiar to longtime Capitals watchers. They scored what amounted to two goals shorthanded.

Edmonton led, 3-2, when Kevin Lowe was assessed a high-sticking penalty with seven seconds left in the second period. On the ensuing power play, Gretzky slipped deep into the Washington zone, unimpeded by the Capitals' point men, and executed an artful midair deflection of Randy Gregg's shot for his second goal of the game and 53rd this season. It was his fifth shorthanded score and the 18th for the Oilers, who lead the NHL.

When Lowe left the penalty box, Gretzky fed him a pass and Lowe was able to slip behind the Capitals on a breakaway. Goalie Al Jensen lost his stick, making it easy for Lowe to shoot into the vacated net and give the Oilers a 5-2 lead. For Gretzky, the assist matched his uniform number--99.

"We were very careless at the start of the third period when we had a chance to get back in the hockey game," said Coach Bryan Murray. "We know what their guys can do out there, but our guys were standing around and it cost us."

The Capitals almost got back in it, as Ken Houston appeared to put the puck in the Edmonton net twice within 90 seconds. However, only one counted and it was not enough.

Edmonton goalie Andy Moog was lying back in the net after Ted Bulley hit a post and Houston's rebound, although blocked by Moog, appeared to cross the goal line. Despite Houston's complaints, referee Kerry Fraser waved it off.

Shortly thereafter, with Edmonton's Paul Coffey off for slashing, Houston converted a pass from Brian Engblom for his 22nd goal. Instead of 5-4, however, it was 5-3 and there was no further scoring until Jaroslav Pouzar hit an empty net with 45 seconds left.

The Capitals' game plan was to put early pressure on the Oilers, who were playing their fourth game in five nights and had been involved in a wearisome battle at Calgary Tuesday.

That thought evaporated after 23 seconds, when Ken Linseman shot from an impossible angle behind the goal line and the puck went into the net after striking Jensen's shoulder.

"We'd had some days off and some guys were rusty," Murray said. "We wanted to play 10 minutes of hockey without giving anything up, so we could get our legs back and take advantage of their being tired from that travel. Instead, we're digging out of a hole from the first shot."

Rod Langway tied the score with a 50-footer before Gretzky scored from the right point on a power play, the puck striking Engblom's stick and deflecting behind Jensen.

Bob Carpenter's 22nd goal, on a power-play setup by Alan Haworth, tied it again before Marc Habscheid's rebound of Glenn Anderson's shot sent Edmonton ahead to stay. Both Jensen and Langway were lying on the ice when Habscheid lifted the puck past Doug Jarvis, who had moved into the crease.

Edmonton's Dave Semenko received a gross misconduct, which promises a future suspension, and was ejected for sticking his fingers in Randy Holt's eyes during a third-period fight. With Laurie Boschman starting a three-game suspension for leading a bench clearing in Calgary Tuesday and Ken Linseman due to start a four-game sentence Friday, the Oilers face personnel problems.

Unfortunately for opponents, including the Capitals March 2 at Capital Centre, Gretzky is in no difficulty.