ARLINGTON, Texas — Tony Romo came into his postgame proudly sporting a T-shirt reading “COWBOYS RUN THE EAST.”

The emphatic performance of Romo and the Dallas Cowboys on Sunday afternoon was worthy of all caps. Romo threw four touchdowns and the Cowboys clinched the NFC East title by blasting the Indianapolis Colts 42-7 at AT&T Stadium.

Dallas improved to 11-4 going into next Sunday’s regular-season finale at Washington. The Cowboys, in the playoffs for the first time since 2009 and in coach Jason Garrett’s five-year tenure, are still in the running for a first-round bye as one of the top two seeds in the conference.

“This is such a long journey and to get to a point to achieve your first goal of winning the division title, a lot goes into that,” said Garrett, who received a Gatorade bath on the field. “The way you play in securing that matters and we played really well.”

Romo became the franchise’s all-time leader in passing yards, surpassing Hall of Fame quarterback Troy Aikman. Romo set the record on a 25-yard touchdown pass to tight end Jason Witten in the third quarter.

“Me and Jason have been through it all together,” said Romo, a former undrafted free agent from Eastern Illinois with 32,970 career yards. “I literally was on the bus from the airport when we arrived in Dallas together for our first rookie minicamp.

“He’s obviously got a special place in my heart. I want more success for him than maybe anybody else on the planet. He deserves it. I want him to have that. For him to be the guy is just a bonus.”

Romo completed a near-perfect 18 of 20 passes for 218 yards and found four different receivers for scores, including a 19-yarder to Dez Bryant. Romo led the Cowboys to touchdowns on their first four possessions.

Dallas running back DeMarco Murray played despite having surgery Monday on a broken left hand. The NFL’s leading rusher scored a touchdown and finished with 58 yards on 22 carries.

“The guys are just playing and executing, and doing their job at a high level,” Romo said.

The Colts (10-5) didn’t have as much on the line with the AFC South title already sewn away, and little-to-no chance to beat out Denver or New England for one of the conference’s top two seeds.

Indianapolis was also without leading receiver T.Y. Hilton, who was resting a hamstring injury. The Colts are at Tennessee next Sunday in their final postseason tune-up.

“I’m thinking about Tennessee first,” quarterback Andrew Luck said. “We’ve got to fix this game, focus on Tennessee and then we can worry about the playoffs.”

Without his favorite target, Luck (15-22 for 109 yards and two interceptions) turned in his poorest performance of the season. Luck didn’t have a touchdown pass for the first time this season and left the game in the third quarter.

Luck came into the game leading the NFL in touchdown passes and yards.

Indianapolis avoided its first shutout since 1993 on running back Zurlon Tipton’s 1-yard touchdown catch from backup quarterback Matt Hasselbeck in the fourth quarter.

The Colts managed only 229 yards — 104 in the first half — and turned the ball over three times.

“I guess it is a bit surprising,” Luck said of the offensive struggles. “There are high expectations for us on the offensive side of the ball, to go out and score every drive, to get points and to move the ball. When we don’t, it’s disappointing.

“It’s a pride thing. When you go out and play like this, it’s a bad feeling. We managed to get a couple of wins early and survive some of those mistakes, but it’s obviously against a good team like the Cowboys you’re not going to. We’ll improve. We’ll get back on track.”

Dallas had the game in hand in the first quarter after jumping out to a 14-0 lead thanks to a long drive and a botched fake by the Colts.

The Cowboys methodically drove 80 yards on their first possession to go up 7-0. Romo completed 5 of 6 passes on the march for 33 yards, and scrambled twice for another 21 yards.

Murray carried it seven times (for only 16 yards) before Romo hooked up with receiver Terrence Williams from 9 yards out for the game’s first touchdown.

Indianapolis had stopped the Cowboys on third down, but a taunting penalty linebacker Jerrell Freeman kept the drive alive.

“Have a foolish penalty and extend the drive,” Indy coach Chuck Pagano said. “And from there it never got any better and we couldn’t overcome a lot of things.”

After the Colts lost five yards on their first three plays, a fake punt had Dallas totally fooled. Punter Pat McAfee lofted a perfect spiral down the sideline, but wide-open safety Dewey McDonald dropped the pass and gave Dallas great field position on the Colts’ 19-yard line.

Romo took the gift and found Bryant on the ensuing play for a two-touchdown advantage.

The lead grew to 21-0 early on Romo’s third scoring strike. A skinny post plus poor tackling by Indy’s secondary enabled receiver Cole Beasley to find the end zone from 24 yards out.

Murray’s 1-yard dive later in the second period capped a 67-yard drive and essentially put the game away. Dallas set a season high for points in the first half by taking a 28-0 lead into the break.

Dallas backup quarterback Brandon Weeden tossed a 43-yard touchdown pass to Williams in the fourth quarter.

What the Cowboys said:

“Statistics are something that are part of the game, but we’re all about winning and losing. At the same time, it’s always an honor any time you’re just mentioned with (Troy) Aikman and (Roger) Staubach or (Danny) White. It’s a fraternity of QBs that is special to be a part of.” — QB Tony Romo, on breaking Aikman’s team record for passing yards.

What the Colts said:

“We’ll find a way to get these things fixed. We obviously know we can’t play the way that we played tonight and expect to do anything down the road.” — Coach Chuck Pagano.

What we learned about the Cowboys:

1. There will be no December collapse this year. Instead of going into the final week needs a win to get into the playoffs, Dallas already clinched the NFC East and remains in play for a first-round bye heading into the regular-season finale at Washington. The Cowboys appear to be peaking at the right time.

2. There is no reason to question DeMarco Murray’s toughness. Injuries have been an issue for Murray in his young career, but the running back suited up a week after breaking his left hand. The NFL’s leading rusher said he was going to play and lived up to his word, gaining 58 yards on 22 carries.

–RB DeMarco Murray was active Sunday despite having surgery on his broken left hand Monday. The NFL’s leading rusher finished with 58 yards on 22 carries. Murray needs 29 rushing yards in the regular-season finale to break Emmitt Smith’s single-season team record of 1,773.

–QB Tony Romo set the franchise record for passing yards at 32,970, passing Hall of Famer Troy Aikman. Romo broke the record with a 25-yard touchdown pass to TE Jason Witten in the third quarter. Romo finished 18-for-20 for 218 yards and four touchdowns in the rout of the Colts.

–WR Dez Bryant caught a touchdown pass for a 12th consecutive game against an AFC opponent. That is the longest interconference streak since the 1970 NFL-AFL merger. Bryant finished with five catches for 73 yards and a 19-yard score Sunday.

What we learned about the Colts:

1. There is not much to take from what appeared to be a preseason game for Indianapolis. The Colts will be playing for seeding and health next week at Tennessee.

2. Falling behind is an issue, as is matching up against the league’s better teams. The Colts are 0-4 against teams that have clinched playoff spots, with losses to Dallas, Denver, Pittsburgh and New England. Indianapolis will have a chance to break that streak in the first round of the postseason.

–WR T.Y. Hilton (hamstring) didn’t play after not practicing all week. He sustained the injury the previous week against Houston.

–QB Andrew Luck didn’t throw a touchdown pass for the first time this season. He completed 15 of 22 pass for 109 yards and two interceptions, and left the blowout in the third quarter.

–TE Dwayne Allen (knee) left Sunday’s game. He will be re-evaluated in Indianapolis.

–LB Jerrell Freeman (hamstring) left Sunday’s game. He will be re-evaluated in Indianapolis.