With five former champions – including the previous four winners – and a pair of same-country clashes, there is plenty to whet the appetite, so the-AFC.com has picked out five things to look out for ahead of the action.

Domestic rivals clash in Japan and China on Tuesday while the 2016 and 2017 champions are among the sides who will take to the field on Wednesday.

Shanghai SIPG's maiden appearance in the AFC Champions League three years ago was ended in comprehensive fashion when they came up against eventual winners Jeonbuk in the last eight.

After a goalless draw at Shanghai Stadium, the K-League side turned on the style to defeat their Chinese Super League visitors 5-0 in Jeonju to sail into the semi-finals.

The holders grip on their Asian crown was close to slipping off completely in the Group Stage of the 2019 edition, but a come-from-behind win over China PR's Shandong Luneng on Matchday Six saw Kashima of Japan extend their stay on the Continental throne until at least the Round of 16.

However, defeating countrymen Sanfrecce and remaining among the final eight will require the Ibaraki club to lift their performances according to Nagaki.

Sanfrecce will go into the first leg at Kashima Soccer Stadium as the form team in the competition, having won five successive games on the Continent to progress to the last 16 on top of Group F.

Next up is Kashima, whose own qualification to the knockout rounds was only confirmed after a come-from-behind 2-1 victory against Shandong Luneng in their final group game as they have yet to hit top form.

In the East, defending champions Kashima Antlers are tasked with fellow J.League team Sanfrecce Hiroshima and Chinese duo Guangzhou Evergrande and Shandong Luneng will also lock horns.

On the other side of the Continent, meanwhile, Qatari powerhouses Al Sadd and Al Duhail face off, while there is also an intriguing Riyadh–Jeddah clash between rivals Al Hilal and Al Ahli. Both matches, however, will not take place until August.

Ahead of the ties, the-AFC.com looks back on five other times the last 16 has pitted clubs from the same domestic league against one another.

It has been a remarkable rise for a club that only arrived in China’s top flight in 2013 and have since gone on to to acquire talent of the calibre of Hulk and Oscar, the Brazilian duo who helped inspire them to their maiden Chinese Super League title in 2018 after three successive top-three finishes.

Arguably, however, no one has been more important in their surge to prominence than Wu Lei, who was the league’s top scorer last year before he signed for La Liga side Espanyol at the beginning of 2019 where he has since gone on to become the first player from his country to score in Spain’s top flight.