But he expressed no regrets Monday about the way the 49ers handled Terrell Owens, even after the Dallas Cowboys star torched them for 213 receiving yards and a tone-setting touchdown in a 35-22 victory a day earlier.

Other teams had slowed Owens by having a cornerback rough him up at the line of scrimmage. But the 49ers at times had Nate Clements line up 10 yards off the line and paid the price.

"It wasn't a mismatch. I think Nate Clements can cover T.O.,'' Singletary said. "If we just said, 'Nate Clements, go over there and get on that line of scrimmage and do not let (Owens) off the line of scrimmage,' I would say that nine times out of 10, Clements would go do that.

"That's not the way we play defense. We played it this way because (Dallas) has so many other guys that can hurt you."

Owens' first catch went for 75 yards and a touchdown, giving the Cowboys the lead for good at 7-6 early in the second quarter. That catch alone gave Owens more yards in a game than he had since Week 2.

By halftime Sunday, he had his first 100-yard game since Nov. 29, 2007.

The problem, Singletary said, was in the execution and not the scheme. He said that on Owens' long touchdown catch, Clements was supposed to keep the receiver in front of him.

On another big play, Donald Strickland was supposed to jam Owens at the line but "rather than knocking the snot out of him, he just reached out and kind of touched him and (the receiver) ran up the field. Mark Roman was chasing after that."

In two career games against his former team, Owens has 12 catches for 356 yards and three touchdowns.

"I thought we had a heck of a plan going into the game,'' Singletary said. "I still think it was a great plan, but you have to execute it. It's as simple as that."

Mike Martz regretted his play calls near the goal line, according to Singletary. The offensive coordinator isn't scheduled to talk to the media until next week but Singletary, speaking on Martz's behalf, said the 49ers should have relied more on a power running game after twice getting a first-and-goal at Dallas' 4-yard line.

On those two chances combined, the 49ers passed four times (all incomplete) and ran just twice before settling for field goals.

"Mike Martz would do it differently,'' Singletary said. "Dallas did some things up front they had not done and we were prepared for something different."

Linebacker Manny Lawson had his best game of the season against the Cowboys with a sack, a tackle for a loss and a fumble recovery. He looks increasingly like a player who should be on the field more often than just third downs.

Singletary agreed, but added that the 49ers have been careful about easing Lawson back to full strength after surgery on a torn anterior cruciate ligament Sept. 26, 2007.

"We're trying to get him on the field more. And we will get him on the field more,'' Singletary said. "The last three weeks or so, he's really been coming on and you can see the confidence."

Chilo Rachal will get another start at right guard, against Buffalo on Sunday, but Singletary hopes it goes better than his first. "He did not play well. He played like a rookie, OK?" the coach said.

Return man Allen Rossum is expected to miss at least one game after suffering a right-ankle sprain in the first half Sunday. The 49ers said they did not know much more about his condition. In Rossum's absence, Delanie Walker handled kickoff-return duties.

Receiver Josh Morgan (groin) and safety Dashon Goldson (knee) are not expected to play against Buffalo. But receiver Arnaz Battle (foot) "has a chance,'' a 49ers spokesman said.

Check out Daniel Brown's 49ers Hot Read blog at blogs.mercurynews.com/49ers . Contact him at dbrown@mercurynews.com