LANDOVER, Md. (AP) - Redskins linebacker Ryan Kerrigan's strip-sack of Cowboys quarterback Dak Prescott was recovered for a touchdown by Preston Smith with just under five minutes left in the fourth quarter Sunday, and Washington held on to edge Dallas 20-17 when a last-second field-goal attempt by Brett Maher went off the left upright.
What would have been a 47-yard kick became a 52-yarder when Louis-Philippe Ladoceur was called for a snap infraction.
That Kerrigan-Smith play that provided the winning points was Washington's fourth sack of Prescott, who appeared to use smelling salts after taking a shoulder to his helmet at the end of a run in the first quarter. Prescott lost two fumbles in the game, including one on an earlier fourth-and-1 keeper.
The Redskins (4-2) won consecutive games for the first time this season and stretched their lead atop the NFC East. They also dropped the Cowboys to 0-4 on the road, 3-4 overall, as they head into their bye week.
Washington won this one thanks to its staunch defense and 99 yards on 24 carries from Adrian Peterson, who helped mask the latest so-so performance from quarterback Alex Smith and a generally iffy offense that was missing three injured playmakers.
The Redskins twice had to settle for short field goals in the second half despite having first-and-goal opportunities. On each of those possessions, Alex Smith missed an open receiver in the end zone from down close.
Washington's QB finished 14 for 25 for 178 yards, including a 23-yard TD on a swing pass to Kapri Bibbs in the first quarter. But there were some questionable decisions, including running out of bounds on third down with 78 seconds left, stopping the clock before a punt gave the ball back to Dallas.
The Redskins limited Ezekiel Elliott, the NFL's No. 2 rusher entering the week, to 34 yards on 15 carries.
He ran 10 times for only 13 yards in the first half, his second-fewest total through two quarters in his pro career.
Prescott was 22 for 35 for 273 yards, with one TD pass and one TD run. He connected with rookie receiver Michael Gallup on a 49-yard score a minute before halftime that made the score 7-all, then - after Kerrigan's key play made it 20-10 - scored on a 1-yard quarterback draw to cut Dallas' deficit to three points with 1½ minutes remaining.
Much earlier, Prescott could be seen waving something near his nose as he headed back into the game after being checked in the blue medical tent for a big blow to his head from cornerback Greg Stroman. Prescott was trying to get to the first-down marker on a third-down run, and he didn't slide at the end of the play.
Prescott was slow to get up, Dallas punted on fourth down, and while Washington had the ball, he was looked at on the sideline.
The QB didn't miss a play, returning for the Cowboys' next possession.
Cowboys: TE Geoff Swaim left with a knee injury. ... CB C.J. Goodwin hurt his forearm.
Redskins: Both Kerrigan (chest) and Preston Smith (ankle) briefly left the game with injuries but returned. ... CB Fabian Moreau hurt his ankle in the last minute of the fourth quarter.
Cowboys: Bye week. Return to host Titans on Nov. 5.
Redskins: At New York Giants.