Arlington, TX (My Sportsbook) - Kory Sheets' nine-yard touchdown run in the final minute was the difference, as the San Francisco 49ers took a 20-13 win over the Dallas Cowboys in preseason play.

Sheets, an undrafted rookie, finished with 42 yards and two scores on 11 carries. Sheets also caught three passes for 18 yards for the Niners, who remained undefeated this preseason at 3-0.

Nate Davis, a fifth-round selection in 2009 out of Ball State, ended with 132 passing yards on 10-of-15 completions. Shaun Hill, recently named San Francisco's starting quarterback, made 9-of-17 throws for 79 yards.

Dallas quarterback Tony Romo completed 11-of-17 passes for 125 yards, but did not have a touchdown and tossed an interception. Backup Jon Kitna threw for an additional 127 yards on 10-of-19 throws, but the Cowboys' lone touchdown came on a three-yard run by Felix Jones in the second quarter. Dallas dropped to 1-2 in preseason contests.

Not at issue during the game was Dallas' video board, which hangs over the playing field. In the Cowboys' preseason game last week, Tennessee's punter A.J. Trapasso hit the massive overhead screen, causing the league's competition committee to meet this past week and issue a series of rule changes.

However, no punter hit it Saturday, though the Niners' Andy Lee hit it during warmups.

The Niners got the ball with under two minutes to play in the contest at their own nine-yard-line, but were the beneficiaries of a pass interference penalty that advanced the ball to the 36.

Davis drove San Francisco downfield, completing a 35-yard pass to Micheal Spurlock that brought the ball to the Dallas 12. On the play, a horse-collar penalty on the Cowboys put the Niners at the six.

Sheets had two runs at the end zone, and at first went back three yards. But on second down he plowed nine yards ahead to notch the game-winning score.

Dallas got on the scoreboard first, as Jones' three-yard dash capped a 94-yard drive that spanned more than eight minutes and started in the opening stanza. Romo was under center for the drive and played the entire first half.

Nick Folk's 25-yard field goal made it a 10-0 game, though Joe Nedney's 42- yarder just before the break got the Niners on the board.

Davis came in late in the third quarter and helped the Niners get their first TD. The 88-yard drive also featured Sheets, who took the ball one yard into the end zone with just seconds remaining in the quarter.

The extra point tied the game heading to the fourth, though Folk's 26-yarder on the opening drive of the stanza made it a 13-10 game.

However, Alex Romero added a 24-yard kick for the Niners with a little more than five minutes to play, and after a Dallas punt, San Francisco embarked on the game-winning drive.

Game Notes

Niners rookie running back Glen Coffee compiled 34 yards rushing on eight attempts and added 27 yards on three catches...Dallas was without wide receiver Roy Williams, who suffered a shoulder contusion in a practice Thursday.