When Pihos returned to Indiana after his military service, he played at the fullback position for the 1945 Indiana Hoosiers football team that compiled the only undefeated record (9–0–1) in Indiana football history, won the program's first Big Ten Conference championship, and finished the season ranked No. 4 in the final AP Poll. He had only two days of practice before his first game back, Indiana's second game of the season, against Northwestern. He scored Indiana's only touchdown in the game, when he caught a pass at the Northwestern five-yard line and dragged three defenders with him over the goal-line. He scored the first two touchdowns in Indiana's 26–0 win over Purdue in the final game of the year. Pihos finished the season having carried the ball 92 times for 410 yards and seven touchdowns. He earned first-team All-America honors from "Yank, the Army Weekly" magazine, and finished eighth in voting for the Heisman Trophy.