The Horned Frogs (51-14), who beat the No. 2 national seed for the second time in five days, will play Vanderbilt on Friday night. TCU would have to beat the defending national champion Commodores twice to advance to next week's best-of-three finals.
Teakell (3-1) took over for starter Mitchell Traver with one out in the fourth and the game tied at 3. The fifth-year senior retired all 13 batters he faced. Preston Guillory worked the final 1 1/3 innings.
With no true No. 3 starter for LSU's third game in Omaha, coach Paul Mainieri decided to pitch by committee and used a CWS record-tying eight. Austin Bain (2-3), the third pitcher for the Tigers (54-12), took the loss.