Alcaraz came from behind twice in the second set before Shapovalov could not continue. The Canadian, ranked 46th, required medical attention at the hip during the tiebreak and played just two more games before withdrawing after one hour and 22 minutes on court. Alcaraz's comeback marked his third straight day of advancing through adversity in Tokyo, matching Rafael Nadal's feat from 2010 and 2011.
The victory guarantees a Spaniard in the final for the seventh time since 1972. Alcaraz, the defending champion and tournament's top seed, will face compatriot Jaume Munar on Monday after Munar defeated Kyrian Jacquet 6-4, 6-2 in just over 90 minutes. The semifinals ensure that either Alcaraz or Munar will win the title.
Alcaraz said little after the match beyond a gesture of goodwill, signing to the camera: "Regresa pronto Denis." The 21-year-old has been hampered by wrist issues earlier this year despite winning the Australian Open and completing a sweep of the four Grand Slams, while Munar has battled arm and jaw injuries.