Going into the matches, only Al Nassr start with a lead while the other three fixtures will kick off all square. Ahead of what promises to be an intriguing few days packed with drama and tension, the-AFC.com has picked five things to look out for.

All four quarter-finals are finely poised with only Saudi Arabia's Al Nassr ahead on aggregate - albeit by just one goal - after the first meetings last month.

As such, Qatar's Al Sadd, Saudi pair Al Hilal and Al Ittihad, Urawa Red Diamonds and Kashima Antlers of Japan along with Chinese Super League duo Shanghai SIPG and Guangzhou Evergrande all remain in the running for a place in the final four.

The two South Americans have once again been on top of their game in the Continental competition and both played vital roles in the first leg comeback that saw the Chinese champions restore parity after going into the interval two goals down.

Oscar drew the foul from countryman Mauricio Antonio that led to Hulk’s first successful penalty, before the latter then converted a second spot-kick following a handball.

Al Nassr will go into the tie at the Jassim bin Hamad Stadium in Doha protecting a 2-1 lead in what promises to be an epic encounter between the league champions of Qatar and Saudi Arabia.

Both had good news to celebrate during the international break with midfielder Nam Tae-hee having resumed training for Qatar Stars League champions Al Sadd while Moroccan forward Abderrazak Hamdallah saw game time for Al Nassr in the Saudi Pro League clash against Al Shabab on Friday.

The last eight tie is finely poised after the first leg of the 'Saudi Clasico' ended 0-0 three weeks ago and Chilean Villanueva, speaking after Al Ittihad fell to a shock 2-1 defeat to Damac in the Saudi Pro League on Friday, said the Jeddah-based club can't afford a similar performance against Al Hilal.

The J.League side secured a goalless draw in the first leg in Guangzhou just over two weeks ago, while their league form has also taken an upturn, having been beaten just once since May as the Ibaraki side have risen to second behind leaders FC Tokyo.

And, just as in 2018, the defending champions could be hitting form at the right time, with Go Oiwa’s team just three games away from a second successive final as they aim to become the first side to defend the AFC Champions League since Al Ittihad in 2004 and 2005.

Much of the hype ahead of Shanghai and Urawa's first meeting revolved around the former's new headline trio of attackers as Brazilians Hulk and Oscar were joined by former West Ham forward Marko Arnautovic, making his debut in Asia's premier club competition.

However, the man who made the biggest impact in the first half was none of the three but instead all-action 27-year-old Nagasawa who had a hand in both of Urawa's opening goals that stunned the hosts. First his free-kick was forced home by Tomoaki Makino, and then it was his incisive pass that picked out striker Shinzo Koroki to double the lead.