SANTA CLARA, Calif. (AP) For the first two drives of the game, Chip Kelly's offense was clicking for the San Francisco 49ers. Blaine Gabbert made big throws, the running game was productive and the team converted third downs with ease.
After jumping out to a quick 14-point lead, everything seemed to stall and the Niners stumbled to their third straight loss, falling 24-17 to the Dallas Cowboys on Sunday.
''We just couldn't keep that momentum going,'' left tackle Joe Staley said. ''It was very frustrating. It was just one of those games.''
The performance over the final three quarters is becoming all too familiar to the 49ers, who have struggled to generate much consistent offense in their first year running Kelly's up-tempo, spread system.
After gaining 143 yards, scoring two touchdowns and all six third-down opportunities in the first two drives, San Francisco was held to 152 yards, three points and just two third-down conversions over the final 43:55.
''We started fast like we wanted to all week,'' Gabbert said. ''Got the run game going. Got some passes in there. Jumped up to 14-0 and just stalled there a little bit. We got to watch the film to really see the reasons why.''
The Niners (1-3) made third downs a priority after failing to convert the first 10 opportunities in a loss at Seattle last week. That seemed to pay off when ran for one on the first drive and then followed up with two long conversions through the air.
He hit Quinton Patton on a 13-yard pass on third-and-12 and then found Jeremy Kerley alone for a 33-yard touchdown on a third-and-7 play.
Gabbert converted another third down with a keeper on the next drive and added a 13-yard pass to Garrett Celek to convert a third-and-9 before Carlos Hyde capped the drive with a 3-yard run on third-and-1 to make it 14-0.
That's about all the offense did all game as San Francisco converted its next third down on the following drive before going 1-for-7 the rest of the way, a big factor in another loss.
The offensive woes could be summed up by the final drives in the fourth quarter. With San Francisco trailing 21-17, the offense took over near midfield with a chance to take the lead.
Gabbert then took a rare deep shot down the field. Torrey Smith got behind the Dallas defense and Gabbert launched a pass his way that could have been a go-ahead touchdown if he had thrown it well. Instead, the pass was well behind Smith and Morris Claiborne managed to recover in time to make the interception .
''We were both frustrated,'' Gabbert said. ''That was a huge play in the game. Every game in the league comes down to one or two plays that change the outcome and that definitely had an impact on it and that's on me. I got to throw that ball to the middle of the field and let him go get it.''
Smith, who hadn't been targeted all game before that point, slammed his helmet in frustration as he went to the sideline.
The Cowboys drove down for a field goal but San Francisco still had a chance to tie it on the next possession. Gabbert quickly moved the team to the Dallas 35 before the two-minute warning.
Gabbert then threw an incomplete pass to Kerley on third-and-6 before connecting on a short throw to Smith, who was stopped 3 yards short of the marker .
Dallas ran out the clock and the Niners were left to lament another loss.
Gabbert finished 16 for 23 for 196 yards with the one TD and one interception. He also ran 12 times for 27 yards and still has Kelly's confidence to remain the starter ahead of Colin Kaepernick.
''I thought Blaine played well besides that one throw,'' Kelly said.
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