ARLINGTON, Texas — After a week in which all the discussion centered on if they were merely a team of the past with an uncertain future, the Seahawks showed Sunday they still have a present worth fighting for.

In what was effectively a playoff game, the Seahawks used a return-to-form performance by the defense to overcome an offense that did little _ well, just enough _ to hold off the Dallas Cowboys, 21-12.

The victory keeps Seattle's hopes for a wild-card playoff spot alive with a simple equation next week _ a Seattle victory at home over Arizona and a win by Carolina at Atlanta. If that happens, the Seahawks have the No. 6 seed in the NFC playoffs.

Anything else and Seattle will be out of the playoffs.

But just staying alive for another week was a huge victory for a Seattle team that a week ago appeared merely lifeless in a 42-7 home defeat against the Rams that essentially handed the NFC West title to Los Angeles.

Against Dallas, turnovers led to all three Seattle touchdowns _ one scored by cornerback Justin Coleman on a pick-six that put Seattle ahead for good in the third quarter. The Seahawks' defense came up big every time Dallas got close to the end zone, forcing five field-goal attempts on six Cowboys possessions inside the 33-yard-line.

In a game Seattle won largely by making fewer mistakes, the Seahawks clinched it in fitting fashion _ a missed 34-yard field goal by Dan Bailey with 5:39 to play that kept Seattle ahead by two possessions. For good measure, Bailey missed another from 48 yards with one minute left when the Cowboys decided to try a field goal on first down with dreams of a recovered onside kick dancing in their heads.

Seattle's offense again did little until the fourth quarter and its 136 total yards were its fewest since 2013.

But what it did in the fourth quarter was enough, a 79-yard, 13-play drive that culminated in a 6-yard pass from Russell Wilson to Doug Baldwin with 11:59 left that helped put the game away.

Until then, the day had been about a Seattle defense that again looked like its old self _ and not just old selves _ with the return of linebackers Bobby Wagner and K.J. Wright producing the desired effect of righting a run defense that had allowed 400 yards the previous two games.

Dallas tried early to replicate that with Ezekiel Elliott _ back after a six-game suspension _ getting 51 yards on 11 carries in the first quarter to twice lead the Cowboys into Seattle territory.

But the defense got big third-down stops time and again and Elliott managed just 46 yards on 13 carries the rest of the game.

The game turned the way Seattle games so often have through the years with a big play by the Seahawks' defense.

Dallas led 6-0 and had the ball at its own 35 late in the second quarter when Byron Maxwell punched the ball out of the hands of Cowboys receiver Dez Bryant after an 8-yard gain.

Wright recovered at the Dallas 43 to set up a quick scoring drive by a Seattle offense that until that point had been held to just 3 net yards.

A Wilson bootleg run of 14 yards got Seattle to the Dallas 11, where Cowboy cornerback Jourdan Lewis was then called for a pass interference penalty on Jimmy Graham in the end zone.

That put the ball at the 1 where on first down Mike Davis fumbled. Wilson, though, alertly dived into the pile to recover it at the 3.

And on the next play, Wilson threw it to the 6-foot-7, 260-pound Graham who was again being covered by the 5-10, 195-pound Lewis. Graham made an easy catch for a touchdown to put Seattle up 7-6 with 1:38 left in the first half.

The Seahawks, though, then quickly gave the lead back as Dallas drove 49 yards on eight plays to set up another 51-yard field goal by Bailey that gave the Cowboys the 9-7 lead at halftime.

Michael Bennett jumped offsides on a third-and-two play to jump-start the drive for the Cowboys.

Dallas dominated all of the numbers at halftime other than turnovers and touchdowns, outgaining Seattle 179-44 and 103-42 rushing with sacks resulting in the Seahawks being credited with just a net 2 yards passing in the first half.

Wilson was just 5 for 11 for 35 yards, losing 33 yards on three sacks.

Seattle took the lead for good when Coleman picked off a badly overthrown Dak Prescott pass and returned it 30 yards for a touchdown with 11:19 to play in the third quarter.

Prescott was simply trying to dump the ball off to Elliott on a second-and-seven play and tossed it far over Elliott's head and straight into the hands of Coleman, who raced untouched into the end zone.

Coleman then celebrated by jumping into an oversized Salvation Army bucket behind the Dallas end zone with teammate Frank Clark happily patting it from the outside.

The act drew a penalty, but the Seahawks were happy to take the trade-off.

Dallas responded with a 39-yard field goal by Bailey to cut the lead to 14-12, taking advantage of a dubious 43-yard pass interference penalty on Coleman drawn by Cole Beasley, who appeared to have a good hold of Coleman's helmet on the play.

That gave Dallas a first down at the Seattle 21. Two Seattle sacks, though, forced the field goal.

Dallas then used a pass interference penalty to get in position to take the lead.

But a Prescott pass went off the bands of Dez Bryant and picked off by Wright at the Seattle 21 to set up the 79-yard drive that put the game away for the Seahawks.