Irfan clocked 1:23:18, finishing more than three minutes behind gold-medallist Wang Zhen (1:19:45) of China. Irfan's timing today was not even his personal best, which stands at 1:20:21 and also happens to be a national record.
Meanwhile, it was heartbreak for Krishnan, who was disqualified for losing contact twice and bending his knees during the race.
The race rules require that the athlete's back toe should not leave the ground until the heel of the front foot has touched down. Krishnan violated this rule twice.
The silver in this event was bagged by Japan's Suzuki Yusuke (1:20:44), while the bronze went to home favourite Kim Hyunsub (1:21:37).