Dallas Cowboys running back Marion Barber (24) fumbles the ball as he is hit by New York Giants defensive end Michael Strahan in the first quarter of an NFC divisional playoff football game. The Cowboys recovered the ball on the play but lost the game, 21-17, Sunday in Irving, Texas.

Irving, Texas ? Peyton Manning has a championship game to be at next weekend after all. He can go watch baby brother Eli guide the New York Giants.

A few hours after the reigning Super Bowl MVP lost his chance to get back to the big game, the less-heralded, often-criticized member of football’s most famous family got the biggest victory of his career. Manning led the Giants past Tony Romo and the Dallas Cowboys, 21-17, on Sunday and into the NFC title game.

“I won’t get tired of hearing that this week,” Manning said. “No one’s given us much credit and probably still won’t. But that’s OK. We like it that way.”

Just 10 days ago, Eli Manning was 0-2 as a playoff quarterback and finishing a season that has had a love-hate relationship with New York fans. Now he has two wins, the admiration of his teammates and an unprecedented amount of support.

“Everybody goes through their ups and downs, and he’s on the upswing right now,” Amani Toomer said. “We’re going to ride him as far as we can go.”

The Cowboys were thinking the same about their quarterback. Instead, their season ended with Romo throwing a fourth-down pass into the end zone and cornerback R.W. McQuarters stepping in front of Terry Glenn for the interception. It marked Romo’s second straight disappointing finish to a playoff game, following his flubbed hold of a short field goal in Seattle a year ago.

Romo came in looking to make up for last season’s finish, to prove his sluggish December was no big deal and to quiet everyone who accused him of mixed-up priorities for joining girlfriend Jessica Simpson in Mexico last weekend.

He couldn’t do it, but it wasn’t all his fault.

The offense stopped drives with penalties, while the defense kept NY drives alive by drawing more flags. There also was sloppy tackling on defense and special teams, dropped passes and wasted timeouts.

The Cowboys stuck to their slow-go game plan to open the second half, but the mistakes began biting them. A dropped pass in the end zone and false start forced Dallas to kick a field goal after a drive that burned 8:07 off the clock.

The Giants trailed only 17-14. After not getting anywhere on their next drive, a 25-yard punt return by McQuarters left Manning only 37 yards from the go-ahead touchdown. He needed only six plays to get it on a one-yard run by Brandon Jacobs, who celebrated by throwing the ball into the play clock.

The Giants will play at Green Bay next week in the NFC title game.