ARLINGTON, Texas -- Russell Wilson sprinted toward the sideline in search a first down that could set up the winning points at Dallas.
The star quarterback made the corner, and the defending NFC champion Seahawks found their way back to .500.
Seattle (4-4) improved to an NFL-best 21-6 in games heading into the bye in its second straight win. The Seahawks will see NFC West-leading Arizona in two weeks.
Seattle receiver Ricardo Lockette had an injury scare, came away with a concussion and was moving his extremities after a vicious block by Jeff Heath on a punt return. It was a tense moment for both teams, with some Seattle players appearing upset at Heath, who flattened Lockette while he was running downfield and had been engaged with another player.
Lockette lay motionless on the field for several minutes and was taken off the field on a motorized cart. He pointed his right hand toward his Seattle teammates on the sideline, and then thrust his index finger high into the air.
"He cleared for concussion stuff, but they have some other tests to do here," coach Pete Carroll said. "We're grateful he's been able to bounce back from that, and he's pretty positive right now."
Later facing third-and-7, Wilson beat Barry Church to the corner, diving past the first-down marker on a 10-yard scramble inside the Dallas 10 near the two-minute warning.
Seattle didn't get a touchdown, but Hauschka's kick came about a minute later than it would have without the critical conversion from Wilson, the NFL's top rushing quarterback who was outgained on the ground with 32 yards to Cassel's 43.
"We shouldn't and wouldn't have expected them to convert those three third-downs situations on that last drive," Dallas owner Jerry Jones said. "We have to figure out a way to play smart enough to win one of these before we get Romo back."
The Dallas offense, held without a touchdown for the second time in five games without Romo, didn't take advantage of two good chances in the fourth quarter.
First, the Cowboys settled for a field goal after defensive end Greg Hardy tipped a pass from Wilson and intercepted it - the first takeaway in five games for Dallas. The only thing that kept him from scoring was Wilson's arm tackle around the ankles the Seattle 16. Three plays later, Dallas got Dan Bailey's fourth field goal and a 12-10 lead.
Cassel kept a couple of the drives to field goals going with his feet, including a career-long 24-yard run, followed shortly by a 12-yarder. But he was 13 of 25 for just 97 yards passing in his second start in place of Romo, who will miss at least two more games with a broken left collarbone. Brandon Weeden lost the first three starts.
"I don't sense desperation and I don't sense panic," Cassel said. "You get on a roll and anything can happen."
After Hauschka's go-ahead kick, the Dallas offense fizzled again on its way to just 220 total yards, the fewest in almost two years.
Cassel was sacked by Irvin on third down and went down again on what appeared to be the final play of the game. Instead, because of a false start, Dallas got one more shot on fourth-and-16 with 12 seconds remaining. Cassel's heave along the sideline was broken up.
"I thought the defense was lights out tonight, making big plays for us," Wilson said. "On offense, when we needed it, we converted and made plays, like the last drive."
Copyright 2015 by The Associated Press