Romo threw a 27-yard touchdown pass to Dez Bryant with 6:35 to go. Anthony Spencer's sack of Andy Dalton forced a punt, and Romo completed four passes on the drive to Bailey's winning kick.
Romo finished 25 of 43 for 268 yards with a touchdown, an interception and three sacks. DeMarco Murray converted a third-and-5 play to extend the final drive and ended up with 53 yards on 21 carries.
Newcomer Josh Brown kicked field goals of 25, 33, 25 and 52 yards for Cincinnati, which wasted an opportunity to move ahead of Pittsburgh for the second AFC wild card.
"They came here in an emotional situation, and you knew they were going to fight all the way," Bengals offensive tackle Andrew Whitworth said. "That game meant a lot to them. They played great."
Dallas played a sloppy game until the closing minutes — nothing out of character there — and had a few especially bad moments.
Defensive coordinator Rob Ryan went onto the field and yelled at a Bengals player who had said something to the Cowboys bench, drawing an unsportsmanlike conduct penalty on Dallas in the third quarter. Dallas also was penalized for 12 men on the field during the drive, which ended with Brown's third field goal and a 16-10 Cincinnati lead.
In the end, a defense that has allowed only three touchdowns in the last four games couldn't hold on. And the Bengals made it tough on themselves by using all three of their timeouts early in the second half, leaving them unable to stop the clock on Dallas' final drive.
Dalton was 20 of 33 for 206 yards with five sacks, one touchdown and an interception that Brandon Carr returned 37 yards to set up Murray's 1-yard touchdown dive in the second quarter.
NOTES: Bailey's game-winner was his second of the season. His 38-yarder beat Cleveland in overtime. It was Bailey's sixth game-winning FG, second in Cowboys history behind Rafael Septien's seven. ... Bryant caught four passes for 50 yards, leaving him with 1,028 yards for the season. It's his first 1,000-yard receiving season and the first by a Cowboy since 2009 (Miles Austin and Jason Witten). ... Bryant has caught a TD pass in five straight games, the longest streak of his career. ... Romo's 25 completions gave him a club-record 349 for the season. He completed his last 12 throws the previous game and his first five on Sunday, setting a club record with 17 straight completions. ... Bengals RB BenJarvus Green-Ellis ran for 89 yards on 12 carries, breaking his streak of three straight 100-yard games.
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