Herb Brooks, the New York Rangers' coach, left the bench duties to his assistants tonight and sought a bird's-eye view of what is wrong with his struggling team. But it was Bryan Murray, the Washington coach, who wished he had been even farther away from the proceedings.

For a change, the Rangers provided some pleasant moments for Brooks and a Madison Square Garden crowd of 17,414, winning on home ice for the first time since Jan. 9. Goalie Eddie Mio stopped 16 Washington shots in the first nine minutes and three goals early in the third period gave the Rangers a 5-4 victory.

It was that close only on the scoreboard. New York had it salted away at 5-2 before Brian Engblom connected with 3:48 left and Bengt Gustafsson completed the scoring with 21 seconds on the clock, after Washington had lifted goalie Al Jensen for a sixth skater.

Although the Capitals' power play was successful twice, the third-period failure of that Jekyll and Hyde unit was the key to the outcome. With New York ahead, 3-2, overlapping penalties to Mikko Leinonen and Robbie Ftorek gave Washington a two-man advantage for 1 minute 37 seconds.

The Capitals did not mount a serious threat, as several shots were deflected by the Rangers' defense, which then cleared the zone. Not long after, with Engblom off for holding, Leinonen scored for a 4-2 lead.

"That was the game," said Murray. "It really burns me. The first time we have a five-on-three we do so well. Then, the second one, we press and get out of position, everybody tries to do-it-myself. If you're two men up in a 3-2 hockey game and you can't score, not even get a dangerous threat, you're in trouble."

The Capitals are not really facing much of an immediate threat from the Rangers, but they missed a chance to apply the coup de grace. They also blew an opportunity to break out of a second-place tie with the New York Islanders. The Rangers, fourth in the Patrick Division, now trail the Capitals and Islanders by 11 points.

The Capitals had a chance pull away early, firing nine shots at Mio in the first three minutes. One of them, off Alan Haworth's stick, got behind Mio, but only after referee Andy Van Hellemond had whistled play dead.

"Mio was such a factor," Murray said. "He almost intimidated our shooters. Alan Haworth and Dennis Maruk had good shots from the slot area, but they missed the net, probably trying to thread them too fine because of the saves Mio had been making."

At the nine-minute mark, the shots were 16-1 and the Rangers had a 1-0 lead, Anders Hedberg scoring on a power-play setup from Robbie Ftorek. It was the only goal on which Jensen, who has yet to beat the Rangers in five tries, was blameless.

Scott Stevens tied it on Washington's 17th shot, an unobstructed 70-footer from outside the blueline that hit Mio's right pad and skipped behind him.

After Eddie Johnstone sent New York back in front with his 17th career goal against Washington--he has only 102 overall--Craig Laughlin deflected Darren Veitch's shot for a 2-2 tie.

The Rangers were two men short at the time, with Ftorek serving a major for spearing Gustafsson in the abdomen. Most of the rest of Ftorek's five-minute sentence was negated by a slashing penalty against Maruk.

The Capitals broke down defensively in the third period as Barry Beck, Leinonen and Mark Pavelich produced the goals that put it beyond Washington's reach.

Beck shot as he crossed the blueline and Jensen, coming out to challenge, allowed the puck to slip between his pads for the tie-breaking goal.

After the Capitals' awful five-on-three power play, Leinonen took advantage of the Rangers' extra man to skate down the right wing, circle outside Stevens and cut in to beat Jensen.

Each team was a man short when Reijo Ruotsalainen got behind Veitch and, with Jensen coming far out, had an empty net in sight, only to shoot wide. When Jensen was slow to return to the goal, Pavelich grabbed the puck and stuffed it in.

The Capitals, who lost here for the first time in more than two years, played without right wing Mike Gartner, whose 248-game streak was ended by an injured left eye. Gartner was examined today, but must await a checkup Monday before the severity of the damage can be determined.