The former University of Texas star responded with 104 yards, putting him over 1,000 for the season.
For all the offensive firepower displayed in Miami's highest-scoring game since getting 49 in the 2002 opener, the biggest play came from the defense.
On the third snap of the second half, with Dallas down just nine, defensive end Adewale Ogunleye ticked the ball away from quarterback Quincy Carter and Jason Taylor returned it 34 yards for a touchdown to make it 30-14.
Miami (8-4) is 1 1/2 games behind New England in the AFC East and 1 1/2 games ahead of Denver and Cincinnati for the conference's final wild-card spot.
The Dolphins have won three straight and are 5-1 on the road, the kind of momentum they need considering their history of disastrous Decembers and a schedule that could set them up for another: at New England a week from Sunday, then home against Philadelphia.
``We're definitely happy with the win, but we're not satisfied,'' Taylor said. ``We know we have to stay poised for the next four games. We feel we're a different football team now than in years past. We think that's going to lead to success in December.''
The Cowboys (8-4) lost for the third time in six games, making the kind of mistakes that coach Bill Parcells hates most. With errors on offense, defense and special teams, the only person who might escape criticism is Richie Anderson, who had the first two-touchdown game of his 11-year career.
``We had no chance at a win,'' Parcells said. ``This team does not have the maturity for this kind of situation. We have young players who do not understand what's going on. ... We were just awful.''
Dallas fell out of a first-place tie with the Eagles in the NFC East, and out of a four-way tie for the best record in the conference.
Plus, the disappointment will linger for 10 days, until the Cowboys play at Philadelphia, and the lopsided loss erases the joy of a 24-20 victory over Carolina that brought tears to Parcells' eyes.
The game-opening interference call against Mario Edwards set a tone for Dallas, too. The Cowboys gave up a TD on the opening drive for the first time in 22 games and never looked like the defense that had allowed the fewest points and fewest rushing yards in the NFL this season.
``It just didn't seem like we were ready to play. That surprised me,'' said Anderson, who had his first rushing touchdown since 1996 and a 25-yard TD catch. ``They played better than we did, more focused than we did and made more plays than we did.''
Fiedler finished 16-of-20 for 239 yards with no interceptions. Not bad for his first start since Oct. 19.
The Dolphins lost that game and Fiedler went out after that with a sprained left knee. Miami went 2-2 with Brian Griese in charge, then was down 13 late in the third quarter against Washington on Sunday night when Fiedler returned and guided the team's biggest fourth-quarter comeback since 1980.
``I don't know if anything has changed since before the injury,'' Fiedler said. ``I just know I've had a good flow with our receivers the past (five) days.''
Fiedler capped the opening series with a 1-yard TD dive. The Dolphins would lead by at least a field goal the rest of the game.
Dallas hung close with Anderson's two second-quarter scores. Fiedler and Chambers answered each time.
First came a well-thrown 39-yarder, then Chambers made a big stretch to haul in a 6-yarder, tapping the tips of his toes while falling out of the back of the end zone with 10 seconds left in the half.
Their third connection was a 35-yarder in the third quarter. Chambers finished with five catches for 96 yards.
Williams' third straight 100-yard game gives him 15 since joining Miami, tying Larry Csonka for the most in team history. It's his fourth straight 1,000-yard season and second in a row in Miami, letting him join Csonka as the only Dolphins players to do it more than once.
Carter was 24-of-40 for 288 yards -- 141 in the fourth quarter -- and two touchdowns, but had three interceptions and the costly fumble. All fourturnovers came in the second half.
Fiedler's rushing touchdown was his 10th for Miami, most by a quarterback in franchise history. ... The Dolphins clinched a 15th straight non-losing season. ... Dallas was allowing 15.3 points, Miami 15.5. ... The Cowboys were giving up 82.4 yards rushing, with only Tampa Bay's MichaelPittman going over 100.
Updated on Thursday, Nov 27, 2003 9:38 pm, EST