ARLINGTON, Texas — Cam Newton is still perfect this season. Tony Romo might be out for good with the same injury that sidelined him for seven games.
Newton got a big boost from a defense that returned two of Romo's three interceptions for touchdowns, and the Panthers ran their NFL-best winning streak to 15 regular-season games with a 33-14 victory over the Dallas Cowboys on Thursday.
Romo injured the same left collarbone that sidelined him for all seven games of a losing streak that damaged the playoff hopes for the defending NFC East champion Cowboys (3-8).
Carolina linebacker Luke Kuechly intercepted two straight passes by Romo, returning the first 32 yards for a touchdown.
Safety Kurt Coleman picked off Romo's second pass of the game and took it back 36 yards for the score to help the Panthers become the 16th NFL team to start a season 11-0.
Before getting hurt, Romo didn't look anything like the only quarterback to beat multiple teams with records of 9-0 or better.
He ended up losing for the first time in four starts this season. He had previously beaten Indianapolis at 9-0 in his fourth career start in 2006 and New Orleans at 13-0 three years later.
Newton did his part as well, getting Carolina's only offensive touchdown on a 4-yard run for a 30-6 lead moments before Romo's injury. He had 183 yards passing with several key third-down conversions and another 45 yards rushing.
On the second play of Dallas' possession after Newton's score, Romo was hit by a blitzing Thomas Davis and went down on his left shoulder. It was eerily similar to the injury he sustained in Week 2 against Philadelphia.
Romo went on injured reserve with a designation to return after the first injury, and the Cowboys couldn't win without him. They were already well on their way to a loss this time a week after Romo ended the seven-game skid in his return. He was 11 of 21 with 106 yards and a 27.2 passer rating.
Carolina led 13-3 when Kuechly and the NFL's leading defense for takeaways put the Panthers firmly in control.
The league's top tackler since joining the NFL in 2012, Kuechly dropped into coverage and easily stepped in front of a pass intended for Terrance Williams before churning up the left sideline and pushing Romo away as he crossed the goal line.
On the next play, Kuechly made a nifty over-the-head catch on a ball thrown to Jason Witten. The linebacker looked a little winded on the return, eventually settling for a 17-yarder that led to the third of Graham Gano's four field goals to put the Panthers up 23-3 at halftime.
It was the fourth time Romo has thrown multiple pick-6s in a game, and the first since a 34-18 home loss in 2012 against a Chicago defense that was among the league's best in forcing turnovers. Romo actually won his first of those, against Buffalo in 2007.
No such chance this time, because Newton kept the Carolina offense moving when Romo wasn't throwing interceptions. Newton had three 24-yard completions on third down, and led the Panthers into end zone after Dallas' Byron Jones was penalized for leaping on top of his linemen when Gano made a 48-yard field goal.
Dallas defensive end Greg Hardy had a quiet game against his former team, finishing without any tackles. He missed the last 15 games last year with Carolina because of his domestic violence case. Hardy signed with the Cowboys as a free agent and served a four-game suspension to start this season.