ARLINGTON, Texas — Tony Romo’s season might be over, and the Dallas Cowboys’ season might as well be.

As for Eli Manning and the New York Giants, everything’s clicking.

Romo broke his left collarbone in the second quarter, then his teammates let a 13-point lead turn into a 41-35 loss Monday night that helps send both teams in opposite directions in the NFC East.

The Giants (5-2) won their fourth straight and moved a full game ahead in the division.

Dallas slumped to 1-5, its worst start since 1989. That was the year Jerry Jones bought the team, Jimmy Johnson took over as coach and the Cowboys went 1-15. Everyone knew that team would stink. This club, however, had Super Bowl hopes.

Any chance of turning this season around ended when Romo was drilled by blitzing linebacker Michael Boley in the second quarter. Recovery time is generally 8 to 10 weeks and, by then, there might not be any reason to rush back.

Romo went down hard on his left shoulder and remained flat on his back. X-rays showed the break before halftime, but he was back on the sideline for the second half, his arm in a sling and covered by a jacket. He wore a headset and tried to encourage teammates, but there wasn’t much to cheer about.

The Cowboys were up 10-7 when Romo left and stretched it to 20-7. Then New York scored on its next five possessions, a 31-point flurry that sent home much of the crowd by the middle of the third quarter.

Manning was 25 of 35 for 306 yards, with four touchdown and three interceptions.

Hakeem Nicks caught nine passes for 108 yards and two touchdowns. Steve Smith caught nine passes for 101 yards and a touchdown, and Ahmad Bradshaw ran 24 times for 126 yards.

Dallas backup Jon Kitna hadn’t played since Oct. 5, 2008, when he was part of Detroit’s winless season. Whether it was the long layoff, being 38 or both, he sure looked rusty.

His first and third passes were tipped. The next time he dropped back, he was sacked for a 10-yard loss, forcing Dallas to punt from its end zone. The Giants took advantage of the short field to score the go-ahead touchdown.

Kitna’s next pass was fumbled by Jason Witten, setting up Lawrence Tynes’ long field goal. It got so bad that there was a mock cheer when Kitna completed a pass for a first down early in fourth quarter.

Kitna threw a pair of touchdown passes to rookie Dez Bryant in the final 3:17, but Dallas failed to recover onside kicks after each. New York got another field goal from Tynes after the first, then ran out the clock after the second.

The craziest part about this game was how many things the Cowboys did right: A club that had only four takeaways all season had five against the Giants. A special teams group that was becoming known for giving up big plays made a huge one — a 93-yard punt return for a touchdown by Bryant.

But they also went 0 for 10 on third downs. And Romo wasn’t the only guy lost to injury. Defensive end Jason Hatcher and left guard Montrae Holland hurt groins. Holland already was filling in for injured starter Kyle Kosier, so the Cowboys had to go with Phil Costa, a rookie free agent making his NFL debut.