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 last night that helped send the 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.

Romo became the fifth quarterback knocked out by the Giants this season. He won’t know a timetable for recovery until more tests are taken today. Jones said he was told six to eight weeks, although he noted that Troy Aikman missed four weeks with a similar injury.

Whenever Romo’s healthy, there may not be any reason to rush back. Only one team in NFL history has recovered from 1-5 to make the playoffs.

"It’ll be tough," said Romo, who has missed three games since replacing Drew Bledsoe as Dallas’quarterback in October 2006. "The train keeps going on. The games are going to be played."

Romo was drilled by blitzing linebacker Michael Boley with 12:07 left in the second quarter. It was a clean hit, but certainly a big shot — Boley was untouched and Romo was vulnerable after having thrown a pass. He went down hard on his left shoulder and remained flat on his back.

"The guard didn’t see me," Boley said. "I came in scot-free. … When he hit the ground, I heard him let out a little scream. I knew something was up, but I didn’t think he was going to lay down. I thought it was a normal hit. After I got up and started running, I looked back and saw he was down."

X-rays showed the break before halftime, but Romo 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. The Giants were ahead by the time Romo’s injury was diagnosed.

"There’s no question we had a letdown when Romo went out of the ballgame," Jones said.

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.

"It just took him a while to get going," Cowboys coach Wade Phillips said. "Once he did, it gave us a chance."

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 own end zone. The Giants took advantage of the short field to score the go-ahead touchdown. His next pass was fumbled by Jason Witten, setting up Tynes’ long field goal. It got so bad that there was a mock cheer when he completed a pass for a first down early in fourth quarter.

Kitna ended up throwing two 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.

With the Super Bowl coming to Cowboys Stadium, and his club coming off a division title and a playoff victory, Jones knew he was headed toward a season he’d never forget. Now, he wishes he could — and he still has 10 games left.

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

But they also went 0-for-10 on third downs.