Felix Jones (28) is chased in Monday's 21-7 Cowboys triumph. (Ronald Martinez/Getty Images)

The Dallas Cowboys rode a suddenly staunch defence 21-7 victory Monday night and saddled the Carolina Panthers with a third straight loss to open the season.

Entering the contest without a sack or a takeaway, Dallas limited the Panthers to six second-half possessions that ended with four punts, an interception and a fumble.

"Everybody on the outside was pressing the panic button," Cowboys linebacker Bradie James said. "But not us.

"We knew we had a bunch of ball left to play. There was still a lot of time to improve."

Cornerback Terence Newman picked off quarterback Jake Delhomme and returned it 27 yards for a touchdown that, with a two-point convert, put Dallas ahead 21-7 with 5:07 remaining.

Panthers wide receiver Steve Smith later admitted that he changed his route from the one called in the huddle.

"I put Jake in a bad situation," he said. "The bottom line is that I [hurt] Jake."

Newman and the rest of the Cowboys defence, much maligned after leading the NFL with 59 sacks last season, preserved the margin by sacking Delhomme twice and forcing him to fumble on Carolina's final drive.

Dallas finished with three sacks — two by rookie linebacker Victor Butler — and three turnovers.

"Before the game, we talked about how our defensive line and linebackers did their job last week and how we didn't do our job," Newman said of the secondary.

"So I told them 'Hey it is on us. We have got to shut these guys down.' We let this team down last week and we have to make up for it this week."

'You have to be ready to go'

Quarterback Tony Romo completed 22 of 33 pass attempts for 255 yards to lead the Cowboys (2-1) to their first win at their brand-new $1.2-billion US stadium, with 90,588 fans on hand.

Felix Jones started in place of injured running back Marion Barber, who suffered a strained left quadriceps in last week's 33-31 loss to the New York Giants, and rushed eight times for 94 yards before leaving in the third quarter with a knee injury.

"You never want your teammates to go down so, when the opportunity is called, you have to be ready to go," said running back Tashard Choice, who had 82 rushing yards and a five-yard major.

"We wanted to make sure we got to the running game and we controlled the game."

Cowboys tight end Jason Witten led all receivers with nine catches for 77 yards.

"We made some adjustments and didn't make many mistakes," said Romo, who was intercepted three times in the loss to New York.

"We had to stop beating ourselves. That was my sole focus this week, to understand why I did certain things and not make those mistakes again and come out and be a better quarterback and help this team win."

'We have to stick together'

Delhomme had similar passing numbers to Romo but was picked off twice and fumbled once.

Dante Rosario hauled in a 25-yard TD pass from Delhomme with 63 seconds left to intermission.

Rosario had three receptions on the scoring drive, equalling his season output to that point.

Running back DeAngelo Williams counted 64 yards on 11 carries for the winless Panthers (0-3).

"We have had three-loss skids before," Panthers head coach John Fox said. "We have to stick together."

Carolina won the NFC South with a 12-4 record last season, but is off to its worst start since 0-7 in 1998.

With files from The Associated Press