In March 1975, Ali faced Chuck Wepner in a bout that inspired the original Rocky. While it was largely thought that Ali would dominate, Wepner surprised everyone by not only knocking Ali down in the ninth round, but nearly going the distance. Ali eventually stopped Wepner in the fading minutes of the 15th round. Following a title defense with Ron Lyle, in July Ali faced Joe Bugner, winning a 15 round decision.
On October 1, 1975, Ali fought Joe Frazier for the third time. Taking place in the Philippines, the bout was promoted as the Thrilla in Manila by Don King, who had ascended to prominence following the Ali-Foreman fight. The anticipation was enormous for this final clash between two great heavyweights. Ali believed Frazier was "over the hill" by that point. Ali's frequent insults, slurs and demeaning poems increased the anticipation and excitement for the fight, but enraged a determined Frazier. Regarding the fight, Ali famously remarked, "It will be a killa... and a chilla... and a thrilla... when I get the gorilla in Manila."
The fight lasted 14 grueling rounds in temperatures approaching 100 °F (38 °C). Ali won many of the early rounds, but Frazier staged a comeback in the middle rounds, while Ali lay on the ropes. By the late rounds, however, Ali had reasserted control and the fight was stopped when Frazier was unable to answer the bell for the 15th and final round (his eyes were swollen closed). Frazier's trainer, Eddie Futch, refused to allow Frazier to continue.