Zhong’s successful spot-kick came after Cui Peng had seen his effort saved by goalkeeper Liu Dianzuo and earned Guangzhou a 6-5 shootout win after the two-legged Round of 16 tie had ended in a 4-4 aggregate draw at the completion of extra time, with Shandong's dramatic 3-2 second leg win ultimately in vain.

Kashima progressed after the tie ended in a 3-3 draw, with Doi’s two goals at Hiroshima Athletic Stadium proving decisive as the holders advanced to last eight against a Hiroshima side that played the final 16 minutes with 10 men following goalkeeper Hirotsugu Nakabayashi’s sending off.

Kashima looked to be on track for a comfortable evening when Doi put them in front 12 minutes before the end of the first half but – inspired by second half substitute Patric – Hiroshi Jofuku’s side almost found a way through.

Goals from Joo Min-kyu and substitute Hwang Il-su saw Ulsan claim a 2-1 victory in the first leg at Saitama Stadium last week as the Korean team secured a first victory in eight away games on the Continent.

Two-time champions Urawa traditionally have a strong record at home in the knockout rounds but the loss leaves them with an uphill task ahead of the match at Ulsan Munsu Football Stadium.

Moon Seon-min struck inside a minute in China to give two-time champions Jeonbuk a vital away goal but the Korean side were pegged back through Weng Shenchao’s equaliser shortly before the interval.

Hosts Jeonbuk have the slightest of advantages as they start the second leg at Jeonju World Cup Stadium knowing that a scoreless draw would see them progress to the quarter-finals for a ninth time.

The K league side are also unbeaten at home in the 2019 competition while Shanghai have yet to win on the road, although the Chinese champions have secured 2-2 and 3-3 draws away from home – results that would ensure they advance.

All four of the last 16 ties are tantilisingly poised - either level or with a team holding a slim one goal advantage - and promise some rollercoaster action to come. The-AFC.com has picked out five things to look out for ahead of the games.

All four games remain tight ahead of the decisive return meetings in the coming days, before which the-AFC.com looks back at some of the numbers that caught the eye as the knockout rounds got underway.

Thanks given, ambitious aims, and supporters praised all feature as the-AFC.com talks to those involved in the latest edition of the Continent's most presitigious competition.