Tony Romo told the coaching staff after pregame warmups he wasn't up to playing with a broken right pinkie. He was in uniform, giving fans false hope, but they were stuck with Brad Johnson.

The 40-year-old backup quarterback couldn't keep up with a suddenly potent, opportunistic St. Louis Rams' offense, throwing three interceptions. Steven Jackson ran for 160 yards on 25 carries with three touchdowns and the Rams (2-4) looked like contenders instead of sad sacks for the second straight game under new coach Jim Haslett in a surprisingly easy 34-14 victory on Sunday.

Owner Jerry Jones admitted after the game that he thought the Cowboys had enough to beat the Rams despite Romo's injury and the suspension of cornerback Adam "Pacman'' Jones. Adding to the woes, Jones said after the game that safety Roy Williams would miss the rest of the season after breaking his right forearm for the second time.

The Rams won 19-17 at Washington last week in their first game since replacing Scott Linehan, ending a run of 17 losses in 20 games and four blowout losses to start the season.

Oshiomogho Atogwe, who had two interceptions, scored the lone touchdown against the Redskins last week on a fumble recovery.

Jackson pulled a quadriceps muscle in the fourth quarter just before Haslett said he was going to take him out, and was to undergo an MRI. But Jackson thought he'd be fine for next week's game at New England.

Marion Barber had 100 yards on 18 carries and the game's opening touchdown for Dallas.

The Rams' 21-point first quarter dwarfed their season output of just 10 points in the first five games. They asserted themselves after Barber accounted for 45 yards on the Cowboys' opening drive, quickly answering on Marc Bulger's first touchdown pass in two starts with a 42-yarder to wide open rookie Donnie Avery.

Jackson added runs of 8 and 1 yards, the Rams' first two touchdowns all season from inside the 20, for a 21-7 lead. The first score capitalized on a short field after Johnson's fumble on a shotgun snap led to a punt from the end zone, and the second came four plays after Will Witherspoon's interception of a tipped pass at the Dallas 18.

Jackson's 56-yard run down the right sideline made it 31-7 midway through the third quarter and gave him three rushing scores for the first time since the 2006 finale. Marc Bulger finished 14-for-19 for 173 yards and a touchdown.