MIAMI, DEC. 20 -- With a bobble, then a look-what-I-found touchdown catch, the Miami Dolphins defeated the Washington Redskins, 23-21, tonight in front of 65,715 at Joe Robbie Stadium.

When wide receiver Mark Duper grabbed his third touchdown pass of the evening from quarterback Dan Marino out of the air and away from the swat of Washington cornerback Dennis Woodberry with 1:07 remaining, the Dolphins had saved their still-flickering playoff hopes and dealt a serious blow to the Redskins' hopes of hosting a playoff game the weekend of Jan. 9-10.

A 67-yard field-goal attempt by Washington kicker Steve Cox, which would have been the longest three-pointer in National Football League history, fell five yards short and wide as time expired in a game that had six lead changes, including three in the fourth quarter.

The Redskins dropped to 10-4, having lost those four games by a total of 11 points. They still have a chance to host a playoff game at RFK Stadium if they beat Minnesota Saturday and Chicago loses at the Los Angeles Raiders Sunday. The Dolphins (8-6) remain alive for an AFC playoff spot.

Marino, who threw for 393 yards against a Redskins defense that tried almost everything to stop him, was nearly intercepted two plays before throwing the winning touchdown pass. Washington free safety Todd Bowles had an interception in his hands at the goal line with 1:19 to play, but cornerback Barry Wilburn crashed into him attempting to intercept the ball. The pass fell to the ground.

On the next play, Marino threw 11 yards to all-purpose back Jim Jensen for a first down at the Washington 6.

Then, he fired to Duper, covered by Woodberry in the front corner of the end zone, just inches across the goal line. The ball bounced off Duper's chest and Woodberry took a quick flail at it as he fell before Duper grabbed the ball for the winning touchdown.

The Redskins took over at their 22 with 55 seconds left and managed to reach the 50 with two seconds remaining when Cox tried his nearly impossible kick. They should not have had the two seconds, however, because the officials mistakenly put two extra seconds on the clock after a penalty on the Redskins with 48 seconds left. The clock ran to 45 seconds when tackle Joe Jacoby was called for a false start. Instead of setting the clock at 48, they put it at 50, in effect giving the Redskins a chance at winning after the game should have been over.

"It came down to plays and they made one more than we did," said Washington Coach Joe Gibbs. "I felt with the wind at Cox's back that a field-goal attempt was as good a chance as a long throw. He's hit 65-yarders in practice."

Had Washington kicker Ali Haji-Sheikh not missed a 38-yard field goal attempt early in the second quarter, the Redskins might not have had to worry about Cox's nearly impossible task.

Speaking of the impossible, the Redskins tried valiantly to stop Marino, the first superstar quarterback they had faced since going to Denver to play John Elway a year ago. Marino completed 22 of 50 passes for those 393 yards and three touchdowns. He brought the Dolphins back from a 14-9 deficit with a 59-yard pass to Duper with 13:29 to play, then threw the winning score after George Rogers' two-yard run put the Redskins ahead, 21-16, with 6:17 to play.

The Redskins did not sack Marino, although they pressured him several times. Washington's streak of 63 consecutive games with at least one sack ended tonight.

"Miami is the best pass-protection team in the NFL," Gibbs said. "We were able to get some pressure on Marino, but he's got such a quick release that it just did not matter."

Quarterback Jay Schroeder, who rallied the Redskins as often as Marino rallied the Dolphins, finished with 272 yards by completing 19 of 38 passes. He did not throw a touchdown pass and found wide receiver Gary Clark only three times for 52 yards, low totals for him.

The first quarter was scoreless, but intriguing. In the second quarter, the Dolphins took a 9-7 halftime lead on Fuad Reveiz's 48-yard field goal and a 26-yard catch by Duper, and Washington scored on Kelvin Bryant's six-yard run. The Redskins went up, 14-9, on Schroeder's three-yard bootleg in the third quarter before the crazy final period.

The Redskins unveiled two semisecret strategic weapons early in the game: a 3-4 defense and rookie running back Timmy Smith.

The 3-4 made its first appearance on the third play of the game, when defensive end Dexter Manley and defensive tackle Darryl Grant left for a play. Usually a 4-3 team, the Redskins used Charles Mann and Markus Koch at end and Dave Butz at nose tackle. The team switched between the 4-3, 3-4 and nickel defense with extra defensive backs Woodberry and Brian Davis.

Assistant head coach/defense Richie Petitbon said last week the team would "mix and match" its defenses in an attempt to stop Marino. They tried nearly everything. They couldn't do it.

Smith spelled Rogers throughout the game, carrying 11 times for 46 yards. Rogers ran 16 times for 59 yards. The team's leading rusher, however, was Bryant, who gained 84 yards on nine carries for a 9.3-yard average. Bryant gained another 69 yards on five receptions, including a leaping fourth-down catch to keep alive the final drive to Cox's long field-goal try.

The Redskins gained 204 yards on the ground, their second-most productive game of the season. They outgained Miami, 472 yards to 459. They had hoped to beat Marino by controlling the ball. They kept the ball nearly 10 minutes longer than the Dolphins, 34:52 to 25:08. But they still couldn't win.

In the second half, the Redskins took the lead, 14-9, on Schroeder's three-yard bootleg with 5:46 remaining in the third quarter, but the Dolphins stormed right back on a 59-yard scoring pass from Marino to Duper to lead, 16-14, with 13:29 left in the game.

On their touchdown, the Redskins drove 78 yards in 10 plays, holding the ball for 5:34, the kind of drive they were hoping for in this game. Rogers was back in the game, but Schroeder threw for the bulk of the yardage on five consecutive completions. He threw five yards to tight end Clint Didier, nine to Bryant, seven and 15 yards to Ricky Sanders, and another 20 to Didier. A personal foul call on safety Bud Brown for a late hit on Didier moved the ball half the distance, to the 5. Rogers gained two yards on first down, then, after a timeout, Schroeder bootlegged around left end after a fake to Rogers.

Two series later, the Redskins were driving again, facing second down and eight at the 24 as the third quarter ended.

But, on the first play of the fourth quarter, Schroeder underthrew Bryant in the end zone and was intercepted by cornerback Paul Lankford. Taking over at their 20, the Dolphins quickly scored on Marino's pass to Duper. Bowles and cornerback Darrell Green missed tackles on Duper at about the Washington 35 before he sped into the end zone untouched the rest of the way for the 59-yard score.

But the Redskins came back two possessions later to retake the lead, 21-16, on an 81-yard drive that was aided by a spearing penalty and personal foul on Brown.

Schroeder ran on a keeper for 16 yards to the Miami 44, then was speared by Brown. Brown pushed an official as he argued and the Dolphins were penalized 30 yards, to their 14. Smith carried twice for nine yards before Rogers came in on third and one for a three-yard gain.

Rogers then gained the last two yards for the touchdown with 6:17 to play.