A game and perhaps a season fell into dire straits quickly tonight for the Washington Redskins.

The San Francisco 49ers pounded the Redskins into a 27-3 halftime deficit, then held on for a 37-31 victory before 59,707 at Candlestick Park.

The 49ers (2-0) were so thoroughly overwhelming in the first half that even the grandest of turnarounds in the second half could not provide victory for the Redskins.

No matter that their offense ignited, improving from producing four first downs in the first half to producing four touchdowns in the second. No matter that wide receiver Art Monk was at his acrobatic best, catching 10 passes for a career-high 200 yards.

This is what matters most to the Redskins right now: they are 0-2 and their pass defense seems in tatters when confronted by a quarterback such as San Francisco's Joe Montana, who completed 24 of 40 passes for 381 yards and two touchdowns. San Francisco outdistanced the Redskins in total yards, 534 to 371.

After two games, the Redskins have allowed 678 passing yards and 931 total yards, and seven touchdown passes. They hadn't lost consecutive regular season games in three years. Tonight's defeat, coupled with a 35-17 loss to Miami in the opener, leaves the Redskins in their most futile condition since an 0-5 start in Joe Gibbs' first year as coach in 1981.

And Sunday the Redskins must play the revitalized New York Giants (2-0) at RFK Stadium, having lost as many games this season as they lost in their entire 14-2 joyride through last season. Strange how in Week 3, the Redskins already have reached a must-win situation.

"That first half," Gibbs said, "is as bad as we've played since I've been here . . . We're losing, but we're losing to good teams . . . The Redskins haven't been playing their kind of ball. We have the players on our team, but we're just not playing to our potential."

The 49ers' coach, Bill Walsh, said, "I'm satisfied with every aspect of our game." Montana added, "We knew going into the game that we were going to try to throw the ball on them, air it out a couple of times . . . In the second half, we tried to go a little more ball control. Our defense played well at the end. They stopped them when they had to."

Momentum never changed in the first half. In the 49ers' first two drives, Montana completed all eight of his passes for 97 yards.

The first drive ended with Wendell Tyler (20 carries for 96 yards) running three yards for a touchdown. San Francisco's second drive ended with Montana scrambling to the right sideline where he seemingly held the ball for an eternity. At last, he threw to Tyler in the middle of the field for a five-yard score.

By and by, the 49ers' running game began to explode, too, ending the half with 111 yards on 21 carries for a 5.3-yard average. The Redskins normally don't yield that much in an entire game. The Redskins say they win or lose by the rush. Tonight they played catchup with the pass and were outrushed, 167 yards to 62.

Meanwhile, the 49ers suffocated the Redskins' offense in the first half. Running back John Riggins was hammered each time he touched the ball, gaining seven yards on four carries. By game's end, he had 12 yards on 10 carries, after being inserted in the second half only to produce two bullish one-yard touchdowns.

Theismann was 24 of 43 for 331 yards and two touchdowns after being under pressure often in the first half.

Theismann was forced to scramble on three third-down plays in the first half. He fell short of a first down each time. On one such scramble, Theismann was hit hard by several defenders and seemed woozy as he rose to his feet. He had suffered a laceration to his head. Jim Hart, the 40-year-old backup, threw on the sideline, but never entered.

San Francisco's Ray Wersching converted field goals of 19 yards and 46 yards in the first half. Near the end of the first half, wide receiver Dwight Clark spun cornerback Anthony Washington into a confused funk and caught a 15-yard scoring pass from Montana. The 49ers led, 27-0, with 1:11 left in the half.

Later in the game, Vernon Dean replaced the oft-beaten Washington. Although Theismann quickly moved the Redskins to Mark Moseley's 38-yard field goal as the half ended, the fourth-largest Candlestick Park crowd ever rose to its feet as the Redskins seemed flat on their backs.

"It's hard to explain why we started to play in the second half," Gibbs said. "We just did. I didn't say anything at halftime. They realized what a hole they were in. They just came out and played hard. They've got great hearts. But it was too little too late."

"We matched them up gunshooter for gunshooter," Theismann said of the second half.

As the second half began, so did the Redskins. First, Theismann led the offense 83 yards in eight plays. He finished with a 14-yard scoring pass to wide receiver Charlie Brown. Brown's first catch of the game brought the Redskins to 27-10 with 10:16 left in the third quarter.

The Redskins' defense began to pressure Montana regularly. At this point, defensive tackle Darryl Grant rushed with a fury and hit him in the chest, forcing an incompletion and forcing Montana out of the game for several plays.

This is when Tyler fumbled and Grant recovered at midfield. Sunddenly, a cool breeze and a Redskins revival blew through the stadium known as Windlestick.

The Redskins drove to Riggins' first one-yard touchdown run, closing to 27-17 with 5:05 left in the third quarter. The drive was made possible by Monk's leaping catch in front of cornerback Mario Clark, for a 30-yard gain to the 20.

On came several crucial mistakes by Redskins cornerbacks Darrell Green and Dean. First, Green allowed wide receiver Mike Wilson to slip past him, curling over the middle. Wilson was off on a 44-yard pass play to the six. The only reason he didn't reach the end zone was that Green's world-class speed allowed him to catch Wilson.

Two plays later, the fourth quarter began with Montana rolling to his right, eluding defensive tackle Dave Butz. As he neared the line of scrimmage at the at the seven, Montana pump-faked twice, freezing linebacker Monte Coleman in the end zone.

Montana raced into the end zone with the seven-yard touchdown run. The lead was inflated to 34-17 with 14:52 left.

Theismann wasn't finished, though. He passed to Monk for 23 yards, then tight end Don Warren for 25 yards, then to Monk again for six yards and to running back Joe Washington for five yards. Riggins entered for his standard one-yard touchdown and with 11:42 the Redskins again were within 34-24.

On came the crucial mistake by Dean. He allowed Clark to catch a pass deep down the left side. This 56-yard gain arranged for Wersching's 38-yard field goal and a 37-24 lead with 9:49 to play. Two touchdowns could still win the game for the Redskins.

After one Redskins drive ended with an incompletion in the end zone to wide receiver Alvin Garrett (cited for offensive pass interference on the play), Tyler committed his second fumble of the game. So much for the 49ers running out the clock.

Defensive end Dexter Manley recovered at midfield with 8:15 left. And once again, Theismann set his receivers in point-producing motion. This time, he threw a 12-yard scoring pass to Virgil Seay, who was curling into the right corner of the end zone. The Redskins trailed by 37-31 with 3:44 to play.

If the defense could hold Montana just this time, perhaps Theismann might get a chance to produce a game-winning touchdown. But it didn't happen.

On third and three from the San Francisco 21, Montana threw to Clark over the middle for an 11-yard gain.

When Craig was held to a three-yard gain, it seemed the 49ers might face third and one from the San Francisco 41. But Manley was cited for a personal foul, and the 15-yard penalty gave the 49ers a first down. Redskins timeouts ran out and Montana just fell on the ball and the victory.

"We've got a short work week," Gibbs said, "and we have to go out and play one of the hottest teams in football in the Giants."

After tonight's game, the Redskins reported the following injuries: Theismann (head laceration that required three stitches); running back Otis Wonsley (thumb laceration); Riggins (mildly sprained wrist); Brown (pulled hamstring); tight end Rick Walker (thigh bruise); linebacker Stuart Anderson (groin pull). Players will be examined by team doctors Tuesday.