Japan emphatically ended Hong Kong's historic run with a 4-0 thumping Wednesday to move into an Asian Games men's football final against South Korea or Uzbekistan.

Hong Kong stunned heavyweights Iran 1-0 in the quarter-finals in Hangzhou to reach the last four for the first time.

The team's surprise run sparked massive interest at home, with shopping malls across Hong Kong showing live screenings of the semi-final.

But Japan were a different proposition for the tournament underdogs, with Shun Ayukawa opening the scoring midway through the first half.

Shota Hino struck twice and Yota Komi added another after the break for Japan, who are looking to win the men's title for only the second time ever.

Hong Kong refused to be overawed by their opponents and had the first chance of the game when Chang Hei-yin fired wide in the fifth minute.

But Japan took control of the game soon after and it was little surprise when they took the lead in the 23rd minute.

A free-kick hit a mass of bodies in the Hong Kong wall and Ayukawa reacted quickest to turn home the loose ball.

Hong Kong had chances at the other end, with Matt Orr trying his luck from a free kick and Li Ngai-hoi heading over the bar.

Japan doubled their advantage less than 10 minutes into the second half when Hong Kong goalkeeper Tse Ka-wing parried Kohshiro Sumi's shot and Hino pounced on the rebound.

Komi made the game safe with Japan's third in the 74th minute, before Hino bagged his second with four minutes remaining.

In the day's second semi-final, Paris Saint-Germain star Lee Kang-in was named in the starting lineup for defending champions South Korea.