It looked like a battle of sick teams, and it was. The Washington Capitals defeated the Winnipeg Jets, 4-3, last night at Capital Centre before a disapproving crowd of 7,440, second smallest of the season.

The Jets are 21st and last in the National Hockey League. The Capitals are 12th, but feeling hot breath behind them to the extent that General Manager Max McNab attended the team meeting in the morning and delivered a pep talk.

Not all the Capitals were there to hear him. Mike Gartner and Ryan Walter were so sick they stayed home, to build up as much energy as possible by game time. They had just enough.

Gartner's rebound of a shot by Walter produced the decisive goal, Gartner's 27th. That came at 4:27 of the third period, following Dennis Maruk's tie breaker 2 1/2 minutes earlier, and provided a necessary cushion, because things got hectic before the two points were safely stored away.

With 5:08 to play, goalie Dave Parro, an absolute sensation for almost six full games, finally proved he was human. Parro allowed a relatively easy backhander by Ron Wilson to slip through his pads and 4-3 with reason to worry.

Fifteen seconds later Parro proved he was not the kind to dwell on past mistakes. If he had not been paying full attention, he would not have stopped a breakaway by Anders Steeen, after Steen had adroitly faked defenseman Jim McTaggart out of his path.

A half-minute later, Parro made the play of the game. Winnipeg mounted a two-on-one break and, at the last possible second, Dave Christian slid a pass through the crease in the direction of wide-open Rick Dudley. Parro quickly got his stick in the way, broke up the play and saved the day.

Winnipeg had some chances of lesser merit before it pulled goalie Markus Mattsson with a minute remaining. Then there was one last sigh, at the other end, as Wes Jarvis, with a fair shot at the empty net, elected to pass to Gartner, who would have had a perfect shot except that he could not handle the pass. It mattered not, as Wilson tripped Gartner a few seconds later, drawing a penalty, and time finally expired.

Gartner was satisfied with one goal, considering it won the game, and he was happier about that than about the fact that 12 hours earlier he had officially become the first Capital elected to an all-star team, being selected to play for the Campbell Conference in the Feb. 10 NHL All-Star Game at Los Angeles.

Besides the ailing Gartner and Walter, Bengt Gustafsson was playing with a strapped-up left shoulder that affected his shooting and Pierre Bouchard was making his first appearance since he injured a knee Dec. 12. It was not the kind of condition that figured to generate a 60-minute onslaught.

For the first 18 minutes of the second period, the Jets outshot Washington, 14-3, and climbed into a 2-2 tie. They put so much pressure on the Capitals in the Washington end that boos were heard, first as a soft tide of dissent and later as a crescendo of disgust. It seemed a bit crass, considering that many of the patrons were using free tickets.

A few minutes with Coach Gary Green improved the Capitals. In the first six minutes of the third period, they built a 10-1 advantage in shots and moved into a 4-2 lead.

Guy Charron, finally unleashed after some impressive efforts in practice, scored the first goal and later made a diving save to block a shot by Morris Lukowich with Parro out of the net after going far out to stop Dudley.

The first goal was memorable, since it came 10 seconds after Washington's Rick Green was sent off for hooking. Charron won the faceoff from Christian in Washington ice and sent the puck into the Winnipeg zone. Mattsson came out, almost to the blueline, but Pronovost beat him to the puck. In doing so, Pronovost wound up with a bad angle and his shot hit the side of the vacated net.

The puck caromed out front, where Lukowich got his stick on it, then did a few ballet steps backward while the puck remained stationary in the crease. Charron, trailing the play, knocked it in.

Bob Kelly netted his 15th goal, first since Dec. 26, in the second period, scooping the puck past Mattsson as he was being knocked down by defenseman Barry Legge.

Maruk's goal was his 30th, the fourth time in six NHL seasons he has reached that plateau. He poked in the puck after Mattsson dropped a routine shot by Howard Walker.