Australia will be a formidable opponent in Saturday's Asian Cup final, but fatigue could be just as big an obstacle to Japan's chances of winning the trophy for a record fourth time.
Japan faces the Socceroos in Doha's Khalifa Stadium four days after a draining semifinal win over South Korea, where extra time and penalties added further weight to legs that looked weary during a difficult second half.
The Koreans raised the tempo after an opening 45 minutes in which Japan had the upper hand, and Alberto Zaccheroni's side found itself struggling to keep up for periods until Hajime Hosogai made it 2-1 early in extra time.