ARLINGTON, Texas (AP) — Dak Prescott threw four touchdown passes, DeMarcus Lawrence returned an interception for a score and the Dallas Cowboys celebrated their clinching of the NFC East title before kickoff with a 56-14 rout of Washington on Sunday night.

The Cowboys (11-4) tied the franchise record for points in a first half while taking a 42-7 lead and frustrating Washington to the point that defensive tackles Jonathan Allen and Daron Payne scuffled on the sideline.

Dallas didn’t need to win to add the division title to the playoff berth that was sealed with San Francisco’s loss to Tennessee three nights earlier. Las Vegas’ 17-13 victory over Denver took care of that about an hour before kickoff.

Prescott and company didn’t seem to care, and scored the franchise’s most points, playoffs included, since a 59-14 victory over San Francisco in 1980.

Washington (6-9) allowed its most points since 2010 in the most-lopsided loss for either team in a storied rivalry played 123 times.

Prescott tied the club record for passing TDs in a half with four before halftime — one each to a running back (Ezekiel Elliott), a tight end (Dalton Schultz), a receiver (Amari Cooper) and a backup tackle (Terence Steele, who was lined up as a tight end when Prescott faked the handoff for an easy 1-yard score ).

Elliott scored twice, getting an 11-yard TD run for a 28-7 lead after opening the scoring on a 5-yard pass.

Taylor Heinicke, making a second consecutive start against Dallas after missing the game in between because of COVID-19, gave up Trevon Diggs’ NFL-leading 11th interception on the first offensive play for Washington, which was playing five days after a coronavirus-delayed loss to Philadelphia.

The Dallas offense took it from there, recording 389 yards before halftime as Prescott broke out of a slump by completing 22 of his first 25 passes and finishing with the most yards passing in a first half in his career with 321. He was 28 of 39 for 330 yards when he left for good in the third quarter.

The Cowboys were already up 14-0 late in the first quarter when Lawrence, a defensive end, deflected Heinicke’s pass with his right hand, corralled the ball and rumbled down the left sideline 40 yards for a TD.

Lawrence was mobbed by other members of his defensive line, just as Steele was by fellow Dallas blockers on his score. It was a different scene for the guys in the trenches for Washington.

The defensive linemen were on the Washington bench when Allen and Payne appeared to exchange words before both got up and Allen, a team captain, threw a punch at his former Alabama teammate.