Seongnam FC v Guangzhou Evergrande Taobao
Guangzhou begin their round of 16 charge deprived of a number of regulars, with midfielders Elkeson and Rene Junior, striker Alan and defender Kim Young-gwon all missing the trip to South Korea. Despite this, coach Fabio Cannavaro still has a strong squad to choose from.
The Chinese outfit began their Champions League campaign in good form, winning their opening three matches in the 'Group of Death'. However, a dip in form saw them draw their following two matches and end the group stage with a 2-0 defeat to West Sydney Wanderers. This mini slump has impacted their league form too, with Cannavaro's side winning just two of five matches thus far in May.
Seongnam endured a poor K-League season, finishing sixth in the standings, but they did book a spot in continental competition next season by winning the Korea FA Cup.
Kim Hak-bum's side did secure progression to the last 16 of the Champions League with a game to spare, but defeat to Gamba Osaka in their final group game meant they had to settle for the runners-up berth in Group F.
FC Seoul v Gamba Osaka
Gamba Osaka head to Seoul on Wednesday looking to get their bid for a first AFC Champions League quarter-final appearance off to a strong start.
Kenta Hasegawa's side qualified for the round of 16 by virtue of claiming top honours in Group F, and the J-League outfit enter the midweek clash on the back of a good run of form, having last tasted defeat more than a month ago.
FC Seoul required an injury time winner from Mauricio Molina in their last group stage game against Kashima Antlers to book their spot in the round of 16, knocking out defending champions West Sydney Wanderers in dramatic fashion.
The South Korean outfit has endured a rocky season thus far, and flirted with the K-League relegation zone for a period, but two wins and a draw in their last three league matches has seen them rise to seventh in the standings.
Naft Tehran v Al Ahli
Saudi Arabia’s Al Ahli were one of only two sides to go unbeaten in the group stage of the 2015 AFC Champions League, and they'll be looking to keep that streak alive when they face off against Naft Tehran in Doha.
While Christian Gross’ side have excelled in continental competition, they will be seething after missing out on the Saudi Pro League title to Al Nassar by a four-point margin after they drew the last two matches of their campaign.
Naft Tehran progressed to the last 16 having first had to qualify for the group stages before securing the runners-up spot in Group B.
Like Al Ahli, they enter Tuesday's clash on somewhat of a disappointing note, having seen the league title slip out of their grasp on Friday. Needing a win over leaders Tractorsazi Tabriz, they could only register a thrilling 3-3 draw, leaving their opponents to take home the spoils.
Al Ahli v Al Ain
In what can perhaps be described as leaving the best for last, Al Ahli of the UAE face off against fierce domestic rivals Al Ain.
Al Ain were undefeated in group play and are on an 11-match unbeaten run in all competitions. As fate would have it, they last tasted defeat against none other than Al Ahli in a United Arab Emirates Super Cup match in late April.
Al Ain will be without suspended duo Helal Saeed and Miroslav Stoch, but striker Asamoah Gyan should feature after recovering from injury.
Al Ahli qualified for the round of 16 by virtue of a second-place finish in Group D, and they have struggled somewhat in the league, currently holding seventh spot in the Arabian Gulf League table.
Fursan will be without the services of goalkeeper Majed Naser who is suspended, but midfielder Majed Hassan is available once more after serving a ban.