Casey Pachall threw two touchdown passes and TCU took advantage of four San Diego State turnovers to hang on for a 27-14 win on Saturday night.
Both of Pachall's scoring throws came in the first half and the Horned Frogs (4-2, 2-0 Mountain West) took a 20-0 lead in the third quarter.
The Aztecs (3-2, 0-1) came within 20-14 in the second half on a pair of touchdown passes by Ryan Lindley, but they got no closer.
Pachall completed 14 of 22 passes for 212 yards with two interceptions as TCU outgained San Diego State, 446-296, including 234 yards on the ground.
TCU set a Mountain West record with its 19th consecutive conference win, breaking a tie with BYU. It was also the Horned Frogs' 15th win in the last 17 road games.