ORCHARD PARK, N.Y. - Apparently, someone forgot to inform the NFL officials what Willis McGahee has gone through in coming back from a knee injury.

That way, they might have given the Buffalo Bills' running back a break instead of ruling he was down before crossing the goal line from 3 yards out.

"I thought they would feel sorry for me, since it's been 19 months," McGahee said. "But I wasn't worried about it. I just told the O-line, `Let's just put it in there. We're not going to be denied.'"

McGahee was true to his word. Following two blockers off left tackle, he burst in from the 1, helping make his NFL preseason debut complete by scoring the go-ahead touchdown in Buffalo's 16-6 victory over Denver on Sunday night.

McGahee finished with 13 carries for 58 yards and a catch for 9 yards. It was an encouraging start for the first-round draft pick, who missed his entire rookie season last year recovering from reconstructive surgery on his left knee.

"It's just another step, and I'm trying to step up the ladder," McGahee said. "Right now I took my second step. And I'm just trying to get to the top."

It has been a long climb for the former Miami star, who some feared wouldn't play again after being hurt in his last college game, the national championship against Ohio State. Considered a top-three pick before the injury, McGahee wasn't taken until the Bills drafted him 23rd overall.

He wasn't cleared for practice until last October, and even then the Bills brought McGahee along cautiously, holding him out of full-contact drills until the first week of training camp earlier this month.

His first true test prior to Sunday came when he scored four touchdowns, all from within the 2, during a controlled scrimmage against Cleveland.

"I think the rust is getting further off," rookie coach Mike Mularkey said. "Comparing him to the scrimmage to the preseason game, I think he started stronger than he did. He ran well."

McGahee's touchdown put the Bills ahead 10-3 with 4:37 left in the second quarter.

His confidence appeared to grow as the game progressed. On the Bills' first drive of the third quarter, McGahee reeled off a strong 16-yard scamper to the left, and followed it up with a few nifty cutbacks, breaking three tackles, for a 6-yard gain.

Count starting running back Travis Henry among the impressed.

"He played good today, didn't he? I like that, for sure," Henry said.

Henry refused to be dragged into a potential running back controversy, even though he has stated that there likely won't be room for both he and McGahee after this season.

"It ain't about me and Willis. It's a team effort," Henry said. "We're cool. I'm the starter. He's a good complement coming in. We're going to be the greatest one-two punch in the league."

Buffalo's Rian Lindell had three field goals, including a 42-yarder to put the game away with 2:10 left.

The Broncos (0-2) settled for Jason Elam's two field goals, continuing to struggle on offense after a sloppy outing last Monday night in a 20-17 loss to Washington.

Starter Jake Plummer went 3-of-11 for 40 yards passing and two interceptions, giving him three in two preseason games.

"What's the date today?" Plummer said testily in response to a reporter's question. "We've got a month left to play. If we go out and stink it up this bad in the first week of the season, then I'll be concerned."

Notes: Bills OT Mike Williams (right foot) did not

play. ... CB Terrence McGee and DE Ryan Denney had interceptions for Buffalo. ... The Broncos opened the preseason at 0-2 for the first time since 1986.