ST. LOUIS (AP) -- Jeff Fisher knew the St. Louis Rams had to keep pushing.
That's why the coach decided to go for it on fourth-and-inches at the Dallas 15 in the third quarter. And why he'd do it again, even though Zac Stacy was thrown for a 1-yard loss.
Fisher's strategic error was only one in a series of mistakes that added up to a 34-31 loss to the Cowboys on Sunday in which the Rams squandered a 21-0 lead.
A flubbed snap, a critical penalty, blown coverage, a dropped pass, a back-breaking interception returned for a touchdown. St. Louis (1-2) did it all.
The only time the franchise blew a bigger lead in a loss came in 1982 when the Rams were in Los Angeles. The Packers rallied from 23 points down, and Denver also wiped away a 21-point deficit that season.
"With games like that, we've got to finish," said St. Louis defensive end Robert Quinn, who led the NFC with 19 sacks last season and has none through three games this year. "I put that on the defense. We get a 21-point lead. No way we should lose that."
Terrance Williams caught a 12-yard touchdown pass from Tony Romo for the go-ahead touchdown with 6:13 to play, and Bruce Carter returned an interception 25 yards for a TD on the next snap as the Cowboys (2-1) tied the biggest comeback in franchise history. It was the largest deficit they've ever overcome in regulation.
On the drive before Williams' touchdown, St. Louis tight end Jared Cook dropped a potential touchdown pass that hit him in both hands in the end zone. A catch would have given the Rams a chance to go up by eight.
"I feel like I let this game slip through my hands and it's my fault," Cook said. "As a man, I'm stepping up to say that."
Third-string quarterback Austin Davis, who threw for 327 yards and three touchdowns in his second career start, let Cook know on the sideline that he shouldn't blame himself and then backed it up in his postgame comments.
"Obviously he can't put this game on himself," Davis said. "You can go down the list. There were numerous plays that we all could have made to change the outcome of the game."
Were there ever. And Davis was among those to blame, with both of his interceptions coming in the fourth quarter -- the one returned by Carter for a score and another on a leaping grab by Morris Claiborne to put the game away.
It all started to unravel late in the first half when rookie Lamarcus Joyner was called for pass interference in the end zone on Romo's third-down pass to Cole Beasley. DeMarco Murray scored on a 1-yard run on the next play, and the Cowboys got the ball back when center Scott Wells rolled a snap between his legs that came nowhere near reaching Davis in the shotgun.
A roughing-the-passer penalty against Eugene Sims put Dallas in range for Dan Bailey's 29-yard field goal that cut the halftime lead to 21-10. Dez Bryant then caught a 68-yard scoring pass in the third quarter when Janoris Jenkins released him on a deep route, and the momentum had fully turned.
On the fourth-and-1 play, Carter was on the sideline being evaluated for a possible head injury and Keith Smith -- signed off the practice squad this week because starting linebackers Rolando McClain and Justin Durant were injured -- was on the field. But the Cowboys still stuffed Stacy.
"We knew we had to keep (putting) points up to stay ahead of these guys," Cook said. "We knew what kind of team Dallas was."
Davis three a 1-yard TD pass to Lance Kendricks on the game's opening drive and added a 51-yard score to Brian Quick before Jenkins' 25-yard interception return, the fifth defensive touchdown in his three seasons, put the Rams up 21-0 with 6:06 to go in the first half.
"Obviously we didn't get the job done. We were probably a play short here or there," Davis said. "It felt good. We were rolling. You just kept waiting to make that big play to get the win. Tip your hat to Dallas. They made those plays and we didn't."