Robert Griffin III threw for 311 yards and four touchdowns, helping the Washington Redskins beat the Dallas Cowboys 38-31 on Thursday.

The Heisman Trophy winner from Baylor made the Cowboys look like an overmatched college team during the decisive second quarter in Griffin’s first pro game in his home state. He got some help from his receivers, including a leaping grab and long run from Pierre Garcon and some nifty footwork in the end zone by Santana Moss.

Tony Romo lost for the first time in six starts on Thanksgiving, despite a career-high 441 yards and three second-half touchdowns, including the longest of his career — an 85-yarder to Dez Bryant. Romo ran in a 2-point conversion after a TD throw to Felix Jones and threw another scoring pass to Bryant to help Dallas close to 35-28 with 8:24 remaining after the Cowboys trailed 28-3 at halftime.

“I thought we had a good chance,” Romo said.

But Griffin answered — twice, actually. After Romo’s long touchdown to Bryant, Griffin threw his fourth scoring pass, a 29-yarder to Niles Paul. The rookie became the first Redskins quarterback to throw four touchdown passes in consecutive games.

After the Cowboys pulled within a touchdown, Griffin drove them into scoring position again, calmly completing three passes for first downs and running 5½ minutes off the clock before Kai Forbath made it 38-28 on a 48-yard field goal.

Dallas drove to a field goal, but DeAngelo Hall easily picked up the onside kick and ran untouched before sliding down short of the goal line, clinching Romo’s third loss in three career 400-yard games. It also was the Cowboys’ first loss to the Redskins in seven games on Thanksgiving.

“That quarterback is obviously a very good player, and they use him well,” Cowboys coach Jason Garrett said. “It was challenging for us to slow those guys down. We didn’t do enough offensively to keep up with them in the first half.”

The Cowboys (5-6) actually contained Griffin in the first quarter, getting a sack and forcing an intentional grounding penalty that gave them good enough field position for an easy drive to a 3-0 lead.

Everything changed on Griffin’s first big NFL play in Texas. He hit Aldrick Robinson in stride for a 68-yard touchdown and a 7-3 lead to spark the first 28-point quarter in 13 years for the Redskins (5-6).

Griffin’s next big throw wasn’t nearly as accurate, but Garcon somehow came down with it and outran the Dallas defense the final 45 yards on a 59-yard score for a 21-3 lead.

Romo’s first interception in four games gave the Redskins a chance to get one more score before halftime when DeAngelo Hall returned it to the Dallas 33 with 30 seconds left. Out of timeouts at the Dallas 6 with 10 seconds left, the Redskins trusted Griffin to try to get a touchdown, and Moss kept both feet in while falling out of bounds for a 28-3 lead with 5 seconds left.

Griffin completed 12 straight passes from the middle of the first quarter to the middle of the third and finished 20 of 28.

It was hard to tell with his final numbers, but the Cowboys did manage to put some pressure on Griffin. They sacked him four times, forced him to sprint out of the pocket a number of times and delivered hard hits after several throws.

The Dallas offense, playing most of the game without Miles Austin after he injured a hip early, never could answer in the decisive second quarter. The Cowboys had only two first downs while the Redskins were scoring four touchdowns.

The Cowboys’ best possession came right after Griffin’s first big play, but Bryant fumbled in the open field at the end of what would have been a first-down catch. DeJon Gomes returned the fumble to the Dallas 49, and Alfred Morris scored from the 1 for a 14-3 lead. Morris had 113 yards on 24 carries.

After forcing a three-and-out on Washington’s first possession, Dallas quickly moved to the Redskins 11, but had to settle for a field goal when Austin couldn’t hang on to a third-down throw from Romo in the back of the end zone on a hit by London Fletcher. Austin took a hard fall and didn’t return.

Fletcher, who also had an interception, extended his consecutive games streak to 235 and made his 190th straight start. He started the day tied with Tampa Bay’s Ronde Barber for most consecutive games, and his starting streak is the league’s longest for linebackers. He left the game later with an ankle injury.