Deion Sanders made a rare mistake in pass coverage, and it cost the Dallas Cowboys.

Sanders, who set up one Dallas touchdown with a 76-yard punt return and made a touchdown-saving tackle, had Marvin Harrison get behind him for a 40-yard touchdown reception on the first play of the fourth quarter, and the Indianapolis Colts held on for a 34-24 victory today.

Dallas (4-3) led 17-3 in the second quarter before the young Indianapolis trio of Harrison, quarterback Peyton Manning and running back Edgerrin James started making the plays for the Colts (5-2), who scored on all but one possession of the second half.

Emmitt Smith's second touchdown run put the Cowboys up 24-21 late in the third quarter before Manning completed passes to Terrence Wilkins, Harrison and Marcus Pollard, taking Indianapolis to the Dallas 40 as the period ended. On the next play, Harrison (six receptions, 85 yards) blew past Sanders and was untouched as he ran to the end zone for the go-ahead score.

"They had been running the ball successfully," Sanders said. "I was looking right into the backfield. The guy just ran past me. It's my fault. I'm not blaming anyone else. He has my vote for the Pro Bowl. He's a great receiver. We couldn't contain him."

On the next series, Troy Aikman was sacked hard by Jeff Burris and went to the bench to clear his head as the Cowboys had to punt. A holding penalty against Dallas, then a face-mask penalty on Sanders brought Indianapolis to the Cowboys 17, and four plays later Mike Vanderjagt's 33-yard field goal put Indianapolis up 31-24.

Jason Garrett relieved Aikman on Dallas's next possession, just his second appearance of the season, and the Colts got the ball back on another punt a minute later. Manning, who passed for 312 yards, hit James on a 54-yarder to the Dallas 25, and six plays later Vanderjagt kicked a 27-yard field goal for a 34-24 lead.

Aikman returned for the final two Dallas possessions, but couldn't engineer a comeback.

Colts defensive end Mark Thomas was injured late in the final period and was taken off the field on a stretcher after a delay of about 10 minutes. He was hospitalized with a concussion.