On March 8, 2014, Ristić, committed to play basketball for the Arizona Wildcats. On Twitter, he announced that he will play his senior year for the Wildcats and finish his education. During his senior season, he was a teammate with future NBA draft first overall pick Deandre Ayton, where Ristić was the starting center that year, while Ayton played as the starting power forward that year. He became the all-time winningest player in program history with 115 victories, surpassing Matt Muehlebach (1988-91) and Kaleb Tarczewski (2013-16) at 110 win. His senior year, Ristic was a second-team All-Pac-12 selection, and a member of the Pac-12 all-tournament team. He also became 28th Wildcat in Arizona history to score 1,000 points and grab 500 rebounds in a career.