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).

The 35-year-old with a surgically repaired back said he would have to wait for more test results before knowing if he broke the collarbone again. He was injured in Week 2 at Philadelphia and said the injury had a similar feel this time.

Coach Jason Garrett wouldn’t rule out Romo returning this season, and said he would play if he was cleared even with the Cowboys unlikely to have a realistic shot to defend their division title.

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.