DENVER (AP) -- The Denver Broncos haven't figured out a way to win without John Elway. Now it appears they'll have to try to win without Terrell Davis, too.

	The Jets' Curtis Martin is pulled down by Tyrone Braxton. Martin ran for 95 yards on 31 carries.

The two-time defending Super Bowl champions fell to 0-4 on Sunday, bowing to the New York Jets 21-13 in a battle of winless teams. Adding injury to insult, the Broncos lost Davis, last year's NFL MVP and rushing champion, to a potentially season-ending knee injury.

The severity of the injury wasn't immediately known. Davis was scheduled for an MRI on Monday morning.

"When it happened, they said there was some looseness in his knee," Broncos coach Mike Shanahan said. "We're going to keep our fingers crossed that it's not an ACL. But at this time it looks like it could be."

Denver and Atlanta, the Super Bowl participants last January, both are 0-4, the first time in a non-strike year that conference champions have done that.

The Jets (1-3) rallied from a 13-7 deficit with two fourth-quarter touchdowns: Curtis Martin's two-yard run, and Rick Mirer's second TD pass of the game, a 16-yarder to Dedric Ward.

The rematch of last year's AFC Championship Game was sloppy and turnover-prone, with the Jets ultimately capitalizing on five Denver interceptions and a fumble.

"It wasn't artistic or anything," Jets coach Bill Parcells said. "We got some turnovers in the second half, and we were able to take advantage of a couple of them. That's what we need to start doing, ball-hogging a little bit. Plus, we didn't have any stupid penalties."

Jets receiver Keyshawn Johnson called the victory "huge."

GAME NOTES

Jets backup cornerback Otis Smith fractured his left shoulder, and backup linebacker Chad Cascadden did not return after suffering a knee injury in the third quarter. Denver kicker Jason Elam became the team's career scoring leader. His seven points on Sunday gave him 748 points, bettering the 742 of Jim Turner (1971-79). The last time Mirer threw two TD passes in a game was Nov. 19, 1995, against Washington, while he was with Seattle.

"To come into this place and beat them -- now everybody in the AFC knows that we have an opportunity to still be in this thing," Johnson said.

Early in the final period, the Jets marched 80 yards for a go-ahead touchdown, thanks to three Denver penalties, including two pass-interference calls against cornerback Dale Carter totaling 45 yards. Martin ran two yards up the middle for the crucial score with 10:52 remaining.

Then came a flurry of turnovers. On the next play from scrimmage, Brian Griese fumbled when sacked by Ray Mickens, and the Jets recovered at the 4. Three plays later, linebacker Bill Romanowski intercepted a deflected pass at the 2. But two plays after that, Aaron Glenn intercepted Griese's long pass and returned it to the Denver 30.

The Jets converted as Mirer threw a 16-yarder to Ward near the left sideline with 5:57 left.

"We had a chance for 21 or 24 points in the first half and didn't get it done," Shanahan said. "Any time you get the ball in the red zone as many times as we did and come away with three points and an interception, that hurts."

Mirer completed 17 of 28 passes for 242 yards with two interceptions. Griese was 15-for-31 for 212 yards with three interceptions.

Bubby Brister subsequently replaced the beleaguered Griese and threw two interceptions of his own.

Davis' 1-yard run and two field goals by Jason Elam gave Denver a 13-7 halftime lead.

Davis was injured late in the first quarter during an interception return by Victor Green. Denver offensive tackle Matt Lepsis made a lunging tackle of Green, but also wiped out the trailing Davis, who was assisted by trainers on the sideline and then limped to the locker room for further examination. He did not return.

Davis' injury overshadowed a weird first half that featured two completions of at least 50 yards, a 71-yard kickoff return by Denver rookie Chris Watson, an exchange of interceptions and the reversal of an apparent Denver touchdown by video replay.

Less than seven minutes into the game, the Broncos led 10-7 in what looked to be a shootout.

On Denver's third play from scrimmage, Griese and Rod Smith hooked up on a 71-yard pass play to the Jets' 4-yard line, but the Broncos had to settle for a field goal.

On New York's first play, Mirer hit Ward on a 50-yard pass, and two plays later Mirer found Johnson on a 26-yard scoring play.

Watson returned the ensuing kickoff to the New York 31, and Davis scored with 8:12 remaining in the period.

The Broncos appeared to have scored a touchdown with 23 seconds left in the half on Griese's 33-yard pass to Smith, but the score was nullified when the replay official said Smith did not get his second foot down inbounds. Elam kicked a 51-yard field goal on the next play.