Thailand thrashed Bahrain 5-0 in their opening game ©AFC

Hosts Thailand began with a big victory on day one of the Asian Football Confederation Under-23 Championship, which is doubling as a qualifier for the men's Olympic tournament.

They eased past Bahrain 5-0 in Group A at Bangkok's Rajamangala Stadium to begin the race for Tokyo 2020 in style. 

Sixteen sides are doing battle at the fourth edition of the age-group event, which offers three places in Japan's capital.

Suphanat Mueanta gave the Thais the lead after just 12 minutes with a right-footed finish, and it was 2-0 shortly after the restart when Supachok Sarachart steered in from a tight angle.

Mueanta made the game safe on 79 minutes by firing home from outside of the area and impact sub Jaroensak Wonggorn then scored a quickfire late double to add extra shine to the score.

He first smashed home from the centre of the box with a minute left in normal time, before a close-range finish in the 92nd minute.

In the day's first Group A game, Australia and Iraq drew 1-1 at Thammasat Stadium in Pathum Thani.

Reno Piscopo gave Australia the lead with a free-kick in the 62nd minute, but 2013 winners Iraq cancelled it out through Mohammed Qasim's superb long-range strike with 13 minutes left.

Iraq hit back to earn a draw with Australia  ©AFC
Iraq hit back to earn a draw with Australia ©AFC

Three players from Australia's under-23 squad were banned from Tokyo 2020 last month after being found guilty of  "unprofessional conduct" during a night out in Cambodia.

Groups B and C begin tomorrow.

In Group B, 2016 champions Japan meet Qatar and Saudi Arabia will play Syria.

Defending champions Uzbekistan kick-off against Iran in Group C, where South Korea will play China.

As Japan have already qualified for Tokyo 2020 as hosts, the remaining three semi-finalists will book their Olympic places should they reach the last four.

If not, the two finalists and the winner of the third-place playoff will advance.

The top two teams in each group will reach the quarter-finals, with the final scheduled for January 26 in Bangkok.

Men's Olympic football features under-23 sides, although three overage players are allowed in the final squads.