PHILADELPHIA — Now the Eagles' problems are much bigger than just Terrell Owens.

Roy Williams intercepted Donovan McNabb's pass and ran it back 46 yards for a touchdown with 2:43 left, leading the Dallas Cowboys to a 21-20 comeback victory over Philadelphia on Monday night in the Eagles' first game since T.O. was told not to return to the team.

The Eagles were in control most of the game, showing poise, running the ball well and playing with the team-oriented balance they talked about all week.

Then Drew Bledsoe connected with Terry Glenn on a 20-yard TD pass with 3:08 left that cut it to 20-14. On the second play after the ensuing kickoff, McNabb's poorly thrown pass was picked off by Williams, who outran McNabb as the quarterback tried to tackle him.

McNabb was hobbling badly after that play, though his injury wasn't immediately known. McNabb, who is playing with a sports hernia that will require surgery, played one more series after the interception, before giving way to Mike McMahon for the Eagles' final possession.

The Eagles had a final chance, but David Akers' 60-yard field goal attempt failed miserably.

When it was over, Dallas coach Bill Parcells shook his head in disbelief as he approached Andy Reid, whose Eagles outplayed the Cowboys — until Dallas' two touchdowns that came 25 seconds apart. The Cowboys lost a Monday night game in similar fashion to Washington in week two, giving up two long touchdown passes to Santana Moss in the waning minutes.

The reigning NFC champion Eagles (4-5) lost their third straight game for the first time since 1999 and fell further behind in the NFC East standings. Dallas (6-3) is tied with the New York Giants for first place, one game ahead of Washington.

For a while, it seemed the Eagles had overcome the distractions caused by Owens' departure and were headed toward an important victory. But McNabb made one of the costliest mistakes of his seven-year career.

Brian Westbrook had 86 yards rushing and one TD and Lamar Gordon ran for 57 yards as Philadelphia's pass-heavy offense tried to offset the loss of its best receiver by keeping it on the ground.

But Philly's wideouts — Reggie Brown and Greg Lewis — combined for just six catches for 57 yards. Owens had 47 catches for 763 yards and six TDs in seven games.

Cowboys coach Bill Parcells was on the sideline, hours after attending his younger brother's funeral in New Jersey. Don Parcells died of brain cancer last week. He was 62.

In their first meeting a month ago, the Cowboys exploited all of Philadelphia's weaknesses en route to a lopsided 33-10 victory. Dallas jumped out to a 17-0 lead and never let up, racking up 456 yards to just 129 for the Eagles.