The Johor-born cyclist was in sight of a podium heading into the final bend – in third spot – when he was taken out by Shinji Nakano of Japan.
Harrie Lavreysen of Holland achieved his dream to become a triple Olympic winner in Paris by romping to gold ahead of Australia’s Matthew Richardson and Matthew Glaetzer.
Lavreysen defeated Richardson in the men’s sprint event earlier this week.
Fourth is still a superb finish for Shah Firdaus, who was only the third Malaysian cyclist to ride in the Olympic final.
Josiah Ng was the first to achieve the feat in Athens in 2004 and it was Azizul who then took over from London 2012 to Tokyo 2021. Azizul took silver in Tokyo and bronze in Rio de Janeiro in 2016.
Shah Firdaus was least expected to contend for the podium with all eyes on two-time Olympic medallist and former world keirin champion Azizulhasni Awang expected to make a strong bid to win the nation’s first gold medal.
However, the pressure shifted to Shah Firdaus after the illustrious Azizul got disqualified for overtaking the derny before it pulled out of the track in the first round heat of men’s keirin on Saturday.
Shah Firdaus, however, put up a gallant charge to clear the quarter-finals and semis to raise hopes for Malaysia.
Though he missed out after finishing fourth in the second semi-final heat but was seen celebrating with both arms raised shortly after he was promoted to third following Kaiya’s relegation for an infringement.