Cahill started Chelsea's UEFA Champions League semi-final first leg against Barcelona because of the injury picked up by David Luiz in the FA Cup semi-final. The match finished 1–0, with Cahill making some crucial tackles in the second half. In the sixth minute of the second leg, Cahill stretched to win the ball and went down with a hamstring injury. Although he tried to run it off, he eventually had to be replaced by José Bosingwa in the 13th minute. Chelsea went on to win 3–2 on aggregate and set up a meeting with Bayern Munich at the Allianz Arena in the 2012 UEFA Champions League Final. Chelsea went on to win the season's FA Cup, beating Liverpool 2–1 at Wembley Stadium in the final, although Cahill missed the match with a hamstring injury. With the suspensions of both defenders John Terry and Branislav Ivanović, questions arose whether Cahill, along with David Luiz, would be fit for the UEFA Champions League Final to fill the gap. On 15 May 2012, he completed his first full training session after three weeks. "We've worked really hard, all day, afternoons, and I'm fortunate enough to be back," he said. "Hopefully, I'll be fit, I will be fit, and hopefully I'll be out there if selected." He started the match and was part of the squad that defeated Bayern on penalties in the 2012 UEFA Champions League Final, giving Chelsea their first ever UEFA Champions League title. He received praise for his performance especially, as he was still suffering from the injury sustained during the semi-final's second leg. During his first half-season at Stamford Bridge, Cahill appeared in 19 matches, scoring two goals and providing one assist in 1,596 minutes on the pitch.