May 25, 2017 0459 GMT
First-half goals from Mohammad Taheri, Ashgar Hassanzadeh and Hamid Ahmadi helped Iran to a 3-0 lead at the break in front of some boisterous support before it turned on the style in the second twenty minutes.
Keshavarz then notched his double before further goals from Hossein Tayebi and Qodrat Bahadori rounded out what was a convincing win for the 10-time champion.
And Iran got off to an explosive start as it scored one of the fastest goals in the history of the competition when it slotted home immediately from the kickoff.
A loose pass from China captain Lu Yue was seized upon by Taheri who guided his shot past Wei Zheng to hand Iran a dream opening.
Five minutes later it doubled its lead following a delay when Wei went down with injury.
Iran took a quick restart and with the Chinese defense still adjusting Hamid Ahmadi fed Hassanzadeh who tucked home his shot at the far post to make it 2-0 after six minutes.
The speed and movement of Iran was causing China all sorts of trouble and only the post prevented the team from going further ahead as Mahdi Javid’s effort missed by the narrowest of margins with five minutes remaining.
The third did eventually arrive though on 17 minutes as Ahmadi smashed home a powerful shot from the right to send his side into the break three goals to the good.
Iran began the second period as it had the first and after several shots that just missed the target it went 4-0 up in the 24th minute as a mistake from Zhao Liang presented the team with a three-on-two situation.
Keshavarz didn't need the extra numbers though as he did it all himself, stroking his shot past Wei with ease and barely 20 seconds later Iran further extended its lead as Reza Sang Sefidi fed Tayebi who made it 5-0.
Tayebi then turned provider in the 28th minute when he laid the ball off to Keshavarz who blasted home his second from midway inside the Chinese half.
Iran was toying with a tiring Chinese side and Bahadori was left completely unmarked with eight minutes remaining and he launched a rocket of a shot that flew past Wei to make it 7-0.
Only some over elaborate passing and wayward finishing preventing Iran from further adding to its tally as it underlined its status as one of the tournament's favorites.