The 2011 winners advanced to the next stage on the back of a 5-3 aggregate win, having defeated the Iranian team 3-1 in the first leg in Tehran.

The game's first shot on target arrived in the 15th minute, when Esteghlal midfielder Mehdi Ghayedi's effort was kept out by Al Sadd goalkeeper Meshaal Aissa.

The hosts took time to settle into the game but showed just how dangerous they can be as the first half went on. Hassan Al Haydos fashioned a goalscoring opportunity out of nothing in the 26th minute, topping off a great run with a stinging shot, forcing a save out of Mehdi Rahmati.

Just a minute later, Al Sadd broke the deadlock through Akram Afif. The youngster picked up Baghdad Bounedjah's lay-off in the box before lashing in an unstoppable shot past Rahmati to give his side a 4-1 aggregate lead.

Esteghlal's reply arrived in the 32nd minute when they equalised with the help of some good fortune. Rouhollah Bagheri's strike was fumbled by Aissa and the ball fell into the net, levelling the score on the night.

When Dalian Shide's Hao Haidong was crowned the first top scorer of the AFC Champions League era in 2003, few might have expected it would take six years before anyone could break his record of nine goals in a single tournament.

In 2009, Leandro's Gamba Osaka was the first to do so by getting into double digits, with his tally being surpassed by five other men since.

The Iranian side came from 2-0 down on aggregate to record a 3-2 victory, with goals from Jalal Hosseini, and Godwin Mensha either side of a Sultan Al Brake own goal helping them turn the tie around at Azadi Stadium.

Coming into the home second leg with a slim one-goal disadvantage, Persepolis found themselves another goal down after 33 minutes as Al Duhail captain Karim Boudiaf capitalised on a poor defensive clearance.

An impressive 3-0 win in the first leg might have some penciling Suwon's name into the semi-finals, but you write off two-time AFC Champions League winners Jeonbuk at your peril.

And it's a mistake that Yeom is adamant his side will not be making at Suwon World Cup Stadium.

The custodian does not have to look far for inspiration, either.

Only last year, ties involving clubs from China and Japan in the AFC Champions League saw a series of extraordinary come-from-behind matches.

Urawa Red Diamonds overcame a 3-1 first leg defeat to win 5-4 on aggregate over Kawasaki Frontale, while Guangzhou Evergrande turned around a 4-0 first leg deficit only to lose on penalties.

Al Duhail took the lead in the 33rd minute after Persepolis defender Shojae Khalilzadeh’s attempted clearance of Murad Naji’s free-kick bounced off Karim Boudiaf and into the back of the net to give the Qataris a crucial away goal.

Bashar Resan nearly equalised for the hosts in the 56th minute after snatching the ball from the Al Duhail defenders and advancing on goal, but his effort from the edge of the box was tipped behind by goalkeeper Amine Lecomte.

The resulting corner kick brought Persepolis their first goal of the quarter-finals after the cross skimmed the heads of strikers Godwin Mensha and Ali Alipour before ending up at the feet of skipper Seyed Jalal Hossein, who converted on the half-volley to bring his side back from the dead in the 57th minute.