Four teams in the West and four from the East remain in contention for glory, with no fewer than four former continental champions still in mix. Ahead of the fixtures, the-AFC.com selects four things to look out for.

Four former continental champions are still in the mix, alongside a side with a 100 percent record, a tournament debutant, a 2017 semi-finalist and a Japanese giant as the competition promises to serve up yet more thrilling action over the second half of the year.

Al Sadd and Esteghlal faced each other last year in the play-off and it was Esteghlal who knocked out their opponents on penalties to reach the group stage.

Both sides have lifted the Asian Club Championship, Al Sadd in 1989 and Esteghlal two years later. But since the inception of the AFC Champions League, Esteghlal's best performance was reaching the semi-finals in 2013, while Al Sadd were the last West Asian champions, lifting the trophy in 2011.

Just one win in four home fixtures does not read like the form of potential AFC Champions League winners, and Kashima Antlers are well aware of the need to rectify that run in Asia's top club competition, according to young star Misao.

Al Duhail and Persepolis both topped their groups and meet for the first time in their history after defeating UAE pair Al Ain and Al Jazira, respectively, in the Round of 16.

Japan’s sole remaining representative on the continent, Kashima, have only once before appeared in the last eight – a decade ago, before the introduction of the Round of 16 – but will be looking to follow in the footsteps of countrymen Urawa Red Diamonds, who won the 2017 edition.

Tianjin, meanwhile, are the only Chinese side left in the competition and their debut appearance can already be considered a major success after suffering just one defeat in eight games en route to the quarter-finals.

Jeonbuk’s Lee Dong-gook and Suwon’s Dejan Damjanovic are the two leading scorers in AFC Champions League history with 36 and 32 goals respectively, since the 2002-03 revamp.

And, although with a combined age of 76, they still remain among the goals in the 2018 campaign.