Rex Grossman knows his reputation as an NFL quarterback.

Too many costly turnovers.

So Grossman entered Sunday's game vs. Dallas – his first Redskins start and his first NFL start since November 2008 – hoping to show that the reputation is not justified at this point of his career.

"I think everyone has doubters and until you prove yourself on a consistent basis, you're always going to have doubters," he said. "I don't care what profession you're in. It's motivation. I'm human. How can you not be motivated to show everybody who's mocking this or talking on the radio or TV thinking they're smart.

"I'm totally motivated to go out and prove not only to them but to myself and my teammates that I'm a bona fide starter in this league and can lead this team to a championship one day."

Named the Redskins' starter ahead of Donovan McNabb last Friday, Grossman had to shake off rust early on in the game. With two turnovers in the first 32 minutes, he was performing to expectations.

Then the offense started clicking and Grossman guided the Redskins to a stunning second-half comeback.

Down 27-7, Grossman threw three second-half touchdown passes – and four overall – to tie the game at 30-30. He even converted two 2-point conversions in the comeback.

His early turnovers were all but forgotten.

The Cowboys managed to pull ahead with David Buehler's 39-yard field goal with 55 seconds remaining in the game.

Grossman and the Redskins had one last opportunity to lead the offense to a game-tying field goal.

The Redskins advanced to the 47-yard line – probably needed about 20 more yards to get in position for the field goal – and on 3rd-and-1 Grossman lofted a pass downfield to tight end Chris Cooley.

The pass was underthrown and Cowboys cornerback Terence Newman leaped up in front of Cooley for the game-sealing interception.

Grossman finished the game with 25-of-43 pass completions for 322 yards, four touchdowns and two interceptions. He was sacked five times and fumbled once.

He had a strong rapport with his wide receivers. Santana Moss caught eight passes for 72 yards and two touchdowns and Anthony Armstrong had five catches for 100 yards, including a 47-yard reception.

Cooley had a quiet first half – no catches – but he was a presence in the second-half comeback, grabbing five passes for 62 yards and a touchdown.

Grossman struggled in the first half, mostly due to shaky pass protection.

His first two turnovers led to Dallas touchdowns, allowing the Cowboys to take command.

The interception came midway through the first quarter.

Grossman started to feel pressure in the pocket and he appeared to throw off his back leg to the sideline, where fullback Mike Sellers was covered by safety Gerald Sensabaugh.

Sellers turned up-field away from the pass, leaving Sensabaugh a clear shot at the ball. He made a diving interception and returned the ball to the Redskins' 27-yard line.

Three plays later, the Cowboys scored their first touchdown of the game to open up a 10-0 lead.

Grossman's second turnover came early in the third quarter with the Redskins starting their opening drive at the 20-yard line.

Once again, he was pressured by the Cowboys pass rush and he rolled left. He stumbled into guard Kory Lichtensteiger who was looking for someone to block.

Suddenly linebacker DeMarcus Ware pounced on Grossman from behind and the ball was dislodged. Defensive lineman Jay Ratliff recovered the fumble at the Redskins' 15-yard line.

Four plays later, the Cowboys crossed the goal line again to build a 27-7 advantage.

Grossman responded by leading the Redskins to three consecutive scoring drives.

His first pass after the fumble was the 47-yard throw to Armstrong, who beat Newman deep.

Two plays later, Grossman connected with Moss on a 10-yard touchdown pass up the middle.

After the Cowboys extended their lead to 30-14 with a Buehler field goal, Grossman completed a 27-yard pass to Cooley to open the Redskins' next drive.

The drive was extended by a roughing the passer penalty on linebacker Anthony Spencer.

On 3rd-and-goal at the Cowboys 5-yard line, Grossman fired a pass to Moss running a crossing pattern in the back of the end zone. Moss pulled in the pass for his second touchdown of the game.

After a 3-and-out by the Cowboys, the Redskins got the ball back with 11:40 left in the game.

Grossman completed a 20-yard screen pass to running back Ryan Torain to move into scoring range.

On 2nd-goal at the Cowboys' 5-yard line, Grossman threw to Cooley on a crossing pattern in the end zone for the touchdown.

The Redskins fooled the Cowboys on the ensuing 2-point conversion, sending fullback Mike Sellers to the flat. He caught Grossman's pass to tie the game.

The Redskins got the ball back with 4:46 left to play.

Grossman and Moss nearly connected on a deep sideline route, but Moss – who was wide open – could not hang on to the ball.

The next two plays, Grossman was sacked both times and the Redskins had to punt.