Griese, who had never won more than two games in a row since becoming the Broncos starter in 1999, connected on 19 of 31 passes for 211 yards and 2 touchdowns, including a crucial 10 play, 80-yard scoring drive in the final three minutes of the game to seal the victory.
This marks the third fourth quarter drive in as many weeks for Griese, who currently leads the NFL in fourth quarter ratings. Ironically, last season Griese ranked dead last in the same category.
"It's becoming a trend for us offensively to put a drive together in the fourth quarter," said Griese. "I would prefer to put the game away in the first half like we should have, but we'll take it."
Helping Griese extend the Broncos winning streak was rookie Clinton Portis, who replaced injured starter Olandis Gary, who left the game early with a sprained left ankle.
Gary's setback opened the door for Portis' career-high afternoon as the young star captured his first NFL 100-yard game and first career NFL touchdown. Portis finished the afternoon with 103-yards on 18 carries, including a one-yard plunge midway through the second quarter, giving Denver a 14 -0 edge.
Buffalo, with the league's number one rated quarterback Drew Bledsoe, found the going tough from the opening kickoff as the Broncos defense kept the Bills high offensive attack in check.
Bledsoe, coming off a franchise-high 463-yard passing performance last week against Minnesota, finished the afternoon with 27 of 41 for 283 yards.
Denver opened up the scoring on the defensive side of the ball as DE Chester McGlockton recovered a Travis Henry fumble and returned it 24-yards for an early 7-0 Broncos lead.
The Bills finally found the scoreboard just before halftime as Bledsoe led a 9 play, 80-yard drive, culminated by a Travis henry one-yard touchdown run. The score cut Denver's lead to 14-7 as the first half came to a close.
The lead was cut even further near the end of the third quarter as Bills kicker Mike Hollis found the range from 38-yards out and suddenly Buffalo threatened to spoil the Broncos undefeated season, trailing 14-10 with just over twelve minutes remaining.
Denver responded in typical Bronco fashion, as Griese led an 11-play, 80-yard drive, connecting with TE Dwayne Carsell from the one-yard line to extend the score 21-10. The drive chewed up nearly 5 ½ minutes off the clock, and shifted the momentum clearly in Denver's favor.
Or so they thought.
With just over eight minutes to go punter Tom Rouen fumbled the snap and Buffalo recovered on the Broncos 12-yard line. Three plays and forty-three seconds later the Bills narrowed the margin as Bledsoe connected with Josh Reed from four-yards out.
Buffalo's two-point conversion attempt failed when linebacker Ian Gold batted down Bledsoe's pass, but the damage had been done and with 7:34 remaining the Bills were just one score away from an upset at 21-16.
With the pressure back on the Broncos, Griese became the man in the spotlight, and the five-year veteran did not disappoint. His final drive of the afternoon covered 80-yards in 10 plays, chewing up another 4:56 off the clock.
During the drive Griese connected on 6 of 9 passes including a 26-yard touchdown strike to Rod Smith to seal the victory. He also kept the drive alive on fourth and five, connecting with Smith on a 6-yard pass to the Bills 31-yard line.
"This is what it's all about, guys stepping up in crunch time when a play is needed," said Broncos fullback Mike Anderson. The win marks the first time that Denver has opened up 3-0 since 1998, when they won their second successive Super Bowl.
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