SAN DIEGO (AP) TCU rolled over San Diego State to stay in the perfect position for a stretch run to a BCS bowl.

Behind Andy Dalton's two touchdown passes and a pair of TD runs, and its top-ranked defense, No. 6 TCU ran its winning streak to 12 games in a 55-12 rout of San Diego State on Saturday.

The Horned Frogs (9-0, 5-0 Mountain West) remained in the chase for their first BCS bowl with a dominating performance.

''That's the big thing,'' Dalton said. ''Our ultimate goal is to end the season undefeated. We have a lot of potential but we have to keep going out and playing like this.''

Dalton led an offense that scored on five of its first six possessions and gained more than 500 yards for the second straight game. The Horned Frogs were ahead of fellow undefeated Boise State, from the Western Athletic Conference, in last week's BCS standings.

The Horned Frogs jumped in front with touchdowns on five of their first six possessions in the first half. Dalton scored on runs of 13 and 7 yards as TCU held a 31-6 halftime lead. He also hit Ryan Christian on TD passes of 44 and 29 yards.

''Early in the season on the road, we didn't start out fast,'' TCU coach Gary Patterson said. ''One of the things I think we are finally doing, especially on offense, is that we are starting faster. That's what you have to do in the last half of the season. You let people hang around, anything can happen.''

San Diego State (4-5, 2-3 MWC) struggled against TCU's top-ranked defense, managing just a 30-yard TD pass from Ryan Lindley to DeMarco Sampson and two field goals by Lane Yoshida.

''That was a long day,'' Aztecs coach Brady Hoke said. ''I haven't been in one of these in a long time. They're a good football team. We got beat in every phase.''

TCU's 11-game winning streak is the nation's third-longest behind Florida's 18-game and Texas's 13-game streak. Iowa had won 13 straight before losing to Northwestern earlier Saturday. The top-ranked Gators took on Vanderbilt later Saturday.

The Horned Frogs have outscored their last four opponents, 178-25. TCU, which gained a season-high 578 yards in last week's 41-0 win at UNLV, had 551 against the Aztecs.

''Right now, we are a confident team,'' Horned Frogs running back Joseph Turner said. ''We feel that no matter what play the coaches call, we are going to be successful.''

Turner led TCU with 79 yards on nine carries and scored on a 4-yard run. Ed Wesley added a 5-yard TD run and Matthew Tucker scored from 30 yards.

Dalton, who left the game late in the third quarter, finished 14 of 20 for 239 yards. He also rushed for 44 yards on five carries. Christian had three catches for 106 yards.

''We have so many athletes on this team,'' Dalton said. ''It makes it easy to get the ball to different people and let them do their thing.''

TCU ran the ball for 312 yards on 53 carries. It was the second straight game the Horned Frogs topped 300 yards rushing, the first time since November 2000, when LaDainian Tomlinson was a senior.

The Horned Frogs' defense, ranked first in the country in total defense, produced four turnovers that led to 13 points. The Aztecs, who had their two-game winning streak snapped, gained just 279 yards.

Lindley completed 16 of 34 passes for 164 yards.