With their fiery leader, Mike Zimmer, sidelined after emergency eye surgery and their playoff hopes fading fast, the Vikings put up a fight Thursday night against the Dallas Cowboys, the NFL's top team. But they lost 17-15 at U.S. Bank Stadium after their two-point attempt in the final minute of the game failed.

The head coach, who had a detached retina in his right eye, underwent his third surgery in a month late Wednesday night. Thursday morning, after a follow-up appointment with doctors and a heart-to-heart chat with General Manager Rick Spielman, the decision was made that Zimmer needed to sit this one out.

Later at the team hotel, Zimmer inspired the team with a pregame pep talk.

"It was really tough to see his emotion, knowing that he wouldn't be there with the team [Thursday]," said special teams coordinator Mike Priefer, who coached in his absence.

Spielman said Zimmer, with doctors orders, planned to monitor the game at home while "resting." However, knowing him, that R&R probably included some cussing while he listened to the game on the radio.

In the first 49 minutes of the game, the Vikings, particularly his defense, gave him some things to cheer about. Through three quarters they kept under wraps the Cowboys' dynamic rookie duo of quarterback Dak Prescott, who was fourth in the NFL in passer rating, and running back Ezekiel Elliott, the league's leading rusher.

And early in the fourth quarter, a third Kai Forbath field goal gave the Vikings a 9-7 lead.

But the game slipped away after a third-down sack by defensive end Danielle Hunter, his second of the night, forced the Cowboys to bring out their punter near midfield. The visitors caught the break they needed when wide receiver Adam Thielen, handling punts with Marcus Sherels sidelined, fumbled on his return.

On the next play, Prescott fired a pass out to wide receiver Dez Bryant, who ran it in for an 8-yard touchdown that put the Cowboys back on top 14-9.

Another poor punt by Jeff Locke, who averaged 32 yards in the loss, followed by a 30-yard run by Elliott, allowed the Cowboys to tack on three more points with 4:15 to play.

Vikings quarterback Sam Bradford threw a 3-yard touchdown pass to running back Jerick McKinnon with 25 seconds left. But after right tackle Jeremiah Sirles was flagged for a false start before the two-point try and a chance to tie the score, Bradford threw it over the head of tight end Kyle Rudolph. Bradford unsuccessfully lobbied for a flag after getting swatted in the helmet on the play. He later said the referee told him he did not see it.

"You've got to make the calls," defensive end Brian Robison said while venting his frustration about the officials after the game. "Bradford gets hit in the face. That's an opportunity for us to score and tie the ballgame, but it doesn't get called."

With the loss, the Vikings fell to .500, putting them farther back in the NFC pack.

The Vikings took a 3-0 lead in the first quarter with a 48-yard field goal by Forbath. Bradford, who this past week said the Minnesota offense needed to produce some "explosive" plays, was 7-for-9 for 79 yards in the first quarter, with the Vikings gaining more than 15 yards on three of those early pass plays.

In the hopes of sparking the NFL's worst offense in terms of yardage, the Vikings also unveiled a new look with four wideouts and no running backs on the field and finally let McKinnon attempt a pass out of the Wildcat. The former college quarterback had Rudolph open downfield but badly underthrew him.

The Cowboys claimed the lead in the second quarter with an 84-yard scoring drive. After Prescott escaped the pocket on third-and-13 and scrambled for a first down, he completed a 56-yard bomb to Bryant, the Pro Bowl wide receiver, after safety Harrison Smith got spun out of position by Bryant's up-and-in route.

Elliott dove into the end zone from 1 yard out to put the Cowboys up 7-3.

On the ensuing drive, Bradford, whose late-minute interception doomed the Vikings in Detroit, threw another bad pick. But a penalty for illegal hands to the face called on Cowboys cornerback Orlando Scandrick bailed out Bradford.

Bradford also got banged up just before halftime, getting sandwiched by Dallas defensive linemen DeMarcus Lawrence and Maliek Collins, with Collins ramming his helmet into the quarterback's rib cage. Shaun Hill subbed in for the rest of the half and soon was sacked. Bradford returned to the huddle after halftime.

Bradford, who was sacked twice by the Cowboys and officially hit nine times, completed 32 of his 45 pass attempts for 247 yards and that late touchdown.

"He proved once again how tough he is," Priefer said.

In the third quarter, Bradford drove the Vikings into field-goal range and Forbath remained perfect in purple, a blocked kick in his debut aside, to pull them within a point of the Cowboys at 7-6. Then in the fourth, after defensive end Brian Robison punched the ball out of Prescott's right hand deep in Cowboys territory, Forbath put them up 9-7.

But the Vikings came up short for their sixth loss in seven games and, with Zimmer out of the mix indefinitely, will probably need to win out.

"They fought to the bitter end and I know Coach Zimmer would have been very, very proud of them," Priefer said. "We'll get this thing righted and keep fighting."

Matt Vensel covers the Vikings for the Star Tribune. matt.vensel@startribune.com