ST. LOUIS -- Tony Romo matched the biggest comeback in Dallas Cowboys history.
Terrance Williams scored the go-ahead touchdown late in the fourth quarter, and Bruce Carter returned an interception 25 yards for a TD on the next snap, capping the Cowboys' comeback from a 21-0 deficit to stun the St. Louis Rams 34-31 on Sunday.
DeMarco Murray's 1-yard run late in the first half began the rally for Dallas (2-1). Dez Bryant caught a 68-yard scoring pass in the third quarter, and Carter's first career interception and touchdown came not long after he was evaluated for concussion-like symptoms on the bench.
Dallas also rallied from a 21-point deficit in overtime in 1984 against New Orleans and 1999 against Washington. It tied the second-largest lead blown by the Rams, who slowed Murray but got burned everywhere else.
St. Louis is 0-2 at home and was whipped 34-6 by Minnesota in the opener.
Murray had 100 yards on 24 carries and lost a fumble for the fourth straight game dating to last season, even after switching from carrying the ball on his left side to the right. He set a franchise record with 253 yards against St. Louis in 2011 and had 175 yards last season.
Janoris Jenkins' 25-yard interception return, the fifth defensive touchdown in his three seasons, put the Rams (1-2) up 21-0 with 6:06 to go in the first half.
Austin Davis got his second straight start in place of Shaun Hill (quadriceps). He cut the Cowboys' lead to three points on a 4-yard pass to Austin Pettis with 2:36 to go, but Morris Claiborne's interception clinched it with 1:02 left.
Romo was 4 for 5 for 40 yards and scrambled 16 yards on third-and-13 on the go-ahead drive. His second-half play overshadowed a third costly INT of the year.
Penalties and a turnover late in the first half helped the Cowboys close the gap.
Murray's 1-yard run came a play after rookie Lamarcus Joyner's interference call in the end zone. Henry Melton recovered a fumble on Scott Wells' flubbed shotgun snap, and a roughing-the-passer call on Eugene Sims got Dallas closer for Dan Bailey's 29-yard field goal.
Bailey set a franchise record with his 28th in a row on a 40-yarder in the third quarter. Chris Boniol hit 27 straight in 1996.
The biggest deficit overcome by a Rams opponent is 23 points by the Packers in 1982, and Denver had a 21-point rally in 1982.