Irfan, who finished 10th in 2012 London Olympics with a national record, clocked one hour 20 minutes and 59 seconds, the second best timing of his career. His national record stands at 1:20:21.
Reigning Olympic champion and one of the home favourites to win the race, Chen Ding fell victim of the hot and humid conditions as he withdrew mid-way in his season-opener.
Another Chinese Li Jianbo, a specialist over 50km and a seventh-placer at London in that distance, clocked 1:18:52 to win the men's race. He was three seconds ahead of teammate and London fourth placer Cai Zelin with Australia's three time Olympic medallist Jared Tallent finishing third in 1:20:41.
Sun Huanhuan of China won in 1:27:36, while compatriot Lu Xiuzhi finished 22 secs behind. Asian record-holder and Olympic bronze medallist Shenjie Qieyang complete the Chinese sweep with 1:28:27.