Kansas City Chiefs quarterback Matt Cassel (7) recovers his own fumble as he is tackled by Dallas Cowboys defensive end Jay Ratliff during the fourth quarter of an NFL football game Sunday, Oct. 11, 2009 in Kansas City, Mo. Dallas won the game 26-20 in overtime. (AP Photo/Charlie Riedel)

KANSAS CITY — Miles Austin looked nothing like a backup making his first career start.

Stepping in for injured wide receiver Roy Williams, Austin caught 10 passes for a franchise-record 250 yards and scored the winning touchdown in overtime of the Cowboys’ 26-20 victory Sunday over the winless Kansas City Chiefs.

In dooming the Chiefs to their 28th loss in 30 games, Austin erased the record of 246 yards that Hall of Famer “Bullet” Bob Hayes set against Washington almost 39 years ago.

“It’s a feeling that’s unbelievable,” he said. “It’s amazing. I never seen that coming today. I was ready today, but you never expect a huge game like that.”

Austin’s tackle-breaking 59-yard catch-and-run from Tony Romo gave the mistake-prone Cowboys a 20-13 lead over the Chiefs with 2:16 left. Then after Matt Cassel’s 16-yard TD pass to Dwayne Bowe tied it 20-20 with 24 seconds to go in regulation, Austin got free on a 60-yard scoring play on Dallas’ second possession in overtime.

Each time, he broke the tackle of cornerback Maurice Leggett.

“It’s very frustrating,” Leggett said. “But we also have to focus on the bigger stuff so we can get better each and every day. Don’t take big jumps and focus on getting 2 percent better every day.”

Kansas City (0-5) is winless for 315 days and has lost eight in a row at Arrowhead Stadium, where the Chiefs were nearly invincible during the 1990s.

Austin is the third Cowboys receiver when Williams is healthy. But he was unstoppable against the Chiefs, who led most of the game but couldn’t take advantage of the many opportunities the Cowboys kept handing them.

Dallas (3-2) was penalized 13 times for 90 yards and Romo overthrew several open receivers. Other passes were dropped. Dallas also muffed a punt and missed a field goal attempt.

“Our guys fought the whole game, but we didn’t do all the right things,” said coach Wade Phillips.

Romo said he noticed on the last play that the defensive back was “really tight on Miles.”

“If you take that chance as a corner, the possibility is there,” Romo said. “I was glad to see Miles take off. It was really exciting and rewarding.”

The Chiefs won the coin toss and received in the overtime but failed to get close enough for a field goal attempt.

“You fight so long for that victory, and it comes down to the wire and you end up losing. It’s like it kills everything,” Chiefs defensive lineman Tank Tyler said.

Late in the fourth quarter, Austin caught Romo’s pass, broke loose from tackles by Leggett and safety Mike Brown, and sped 59 yards to give the Cowboys their first lead of the day.

Then Cassel swept the Chiefs down the field, hitting Bowe in the end zone on fourth-and-7. Ryan Succop, who had a 53-yard field goal attempt blocked by Jay Ratliff right before Dallas’ last TD in regulation, kicked the extra point for the tie.

Umpire Bill Schuster left the field for several plays in the first half. Schuster was standing in front of the pile when Kansas City’s Tamba Hali rolled up on him from behind, knocking him flat.