PITTSBURGH — Brett Favre, Adrian Peterson and the Minnesota Vikings were anything but perfect.

The Vikings couldn't gain a half-yard when it might have turned the game, then watched the Steelers' big-play defense end their unbeaten season with two long touchdown returns in the final 6 1/2 minutes.

LaMarr Woodley's 77-yard fumble return and Keyaron Fox's 82-yard interception return on turnovers by Favre allowed the Steelers to thwart Minnesota's repeated comeback attempts, 27-17, yesterday.

The anticipated quarterback showdown between Favre and Ben Roethlisberger turned into a defensive duel. And the Super Bowl champion Steelers (5-2) are tough to beat in any game that's decided by defense.

The Vikings (6-1) had a first down inside the Steelers 1 during the third quarter but settled for a field goal that kept Pittsburgh in the lead at 13-10. Peterson got the ball only once.

"That's the biggest point of the game," Steelers safety Ryan Clark said. "You have the best running back in the world and you don't give it to him. They're saying they can't beat us running, and that's a major statement when you have the guy they have back there."

Woodley's fumble return, with the linebacker huffing and puffing for the final 30 yards after Brett Keisel stripped Favre of the ball, put the Steelers up 20-10 with 6:23 remaining.

But, the Vikings weren't done. Percy Harvin returned the kickoff 88 yards for a touchdown, and Minnesota drove to the Steelers 18 with just over a minute left, and the Vikings' biggest win of an improbably good season awaited.

But Fox intercepted Favre's pass intended for Chester Taylor and returned it almost the length of the field, with nearly every Viking except Favre in pursuit to end the rally.

"There were a lot of what ifs, a lot of reasons we didn't win," Favre said. "The red zone was one of them. They're physical, and they were as good as we thought they'd be. ... When I came here and looked at our schedule (and saw the Steelers game), I went, 'Oh-h-h.' "