DENVER -- He's 38, more prone to injury and less quick to recover, and his uncanny elusiveness in the pocket has diminished.

But he's still John Elway, as he proved Sunday in rallying the unbeaten Denver Broncos to a 35-31 victory over the Kansas City Chiefs."The old man over there," said tight end Shannon Sharpe, nodding in Elway's direction in the relieved Denver locker room. "You all keep talking about it's time for him to hang it up, but the guy's got plenty of life in that arm."

Elway has been sidelined for all or part of six games this season because of injuries, and the Broncos didn't seem to miss him. But on Sunday, they needed one of Elway's trademark fourth-quarter comebacks, and he delivered.

Elway drove his team to two touchdowns in the final 6:48 as the Broncos kept their perfect season intact. They became only the third 13-0 team in NFL his- tory, joining the 1934 Chicago Bears and 1972 Miami Dolphins.

Denver, which overcame deficits of 14-0, 21-7 and 31-21, clinched a first-round bye and home-field advantage throughout the playoffs.

Elway completed 22 of 32 passes for 400 yards and two scores, including the game-winner -- a 24-yard pass to Sharpe with 3:34 remaining.

"To be able to come through when we needed the passing game, it's nice to make the plays when you have to make them," Elway said. "It's been so long since we've been in a game like this. This was fun."

It was Denver's toughest game to date. The Broncos had trailed in only three games all season, and never by more than six points.

Trailing 31-21, the Broncos got big plays from both their offense and defense.

Elway's medium-range pass to Willie Green turned into a 50-yarder when Green broke Dale Carter's tackle, taking it to the 1, where Terrell Davis scored his third TD of the game with 6:48 remaining.

Denver's defense, vulnerable to the Chiefs' short passing game most of the day, held and forced a punt, and Denver took possession at the 50.

Orchestrating the 47th game-saving drive of his career, Elway put the Broncos in the end zone five plays later.

Sharpe's touchdown catch came on a third-and-1 play.

The Chiefs, who had exhausted their timeouts, mounted a last-gasp drive to the Broncos' 36, but Rich Gannon was sacked on fourth down by Steve Atwater and Alfred Williams.

Of Elway's 47 comeback drives, nine have come against a Marty Schottenheimer-coached team, including two in Cleveland.

"I have the greatest admiration in the world for him," the Chiefs coach said of Elway. "It has nothing to do with his skill. It's that the guy is the most competitive individual I have ever known. He is the finest competitor I have ever seen in professional sports."

Denver's Rod Smith caught eight passes for 165 yards and Ed McCaffrey caught six for 103 yards.

Davis, the NFL rushing leader, had 88 yards on 24 carries to boost his season total to 1,654 yards. Davis scored on three 1-yard runs, giving him 59 career touchdowns to break Marcus Allen's NFL record for most touchdowns in the first four years of a career. Allen had 58.