The round of 16 kicks off in the AFC Champions League with Jeonbuk Motors, the only former winners to reach this stage, entertaining Kashiwa Reysol in the first leg. Fellow K League participants FC Seoul, meanwhile, travel to China to take on Beijing Guoan, while in west Asia a pair of seasoned campaigners meet, with Al Gharafa welcoming Al Shabab.

Having progressed to the last 16 for the first time, a quintet of sides face daunting tasks. Central Coast Mariners, for example, will have their work cut out against last year's quarter-finalists Guangzhou Evergrande, while Al Shabab Al Arabi face a tough duel with Iranian champions Esteghlal. Join as we preview these enticing match-ups across the continent.

The match
Buriram United-Bunyodkor
Cliche or not, Buriram’s meeting with Bunyodkor befits the David versus Goliath image. Mirjalol Kasimov’s visitors boast a proud Champions League record, having made it to the knockout stage in all six previous attempts. The hosts are, for their part, the first Thai side to reach this stage since BEC Tero Sasana in 2003.

Considering their brilliant showings so far, though, few doubt that Buriram’s ability to spring a surprise. The Thai outfit did, after all, stun Kashiwa and Guangzhou Evergrande in the last edition, before edging Jiangsu Sainty to seal their maiden knockout stage appearance. Furthermore, they can take heart from BEC's heroics in the inaugural tournament, when the unfancied Thais emerged 4-2 semi-final victors against another Uzbek outfit, Pakhtakor.

Scott Cooper, who recently replaced Atthaphol Puspakom as Buriram’s coach, enjoyed a good start on Saturday with a 4-1 defeat of Osotspa. However, the suspensions of captain Suchao Nutnum and Spanish midfielder Carmelo Gonzalez do provide him with cause for concern. Kasimov must also modify his line-up, with defender Akmal Shorakhmedov suspended.

The other attractions
In west Asia, the matchday is marked out by a trio of clashes between teams from Qatar and Saudi Arabia. Qatari El Jaish and Lekhwiya, both of whom progressed beyond the group phase for the first time, meet Saudi duo Al Ahli and Al Hilal respectively. Despite losing Saturday's Emir Cup semi-final meeting against Al Rayyan, El Jaish welcome Al Ahli brimming with confidence, having crushed Saudi giants Al Shabab 3-0 in the group phase. Lekhwiya, too, can draw inspiration from the four points they won from Al Ettifaq when they line up against Al Hilal.

Dominating attention in the two countries and beyond is, of course, the re-match between Al Gharafa and Al Shabab. The former came out on top in last year's group meetings, claiming four points, including a 2-1 home win from two legs. Captained by Qatari international Lawrence Quaye, and with Djibril Cisse spearheading the attack, the hosts have proved a formidable force. The visitors, though, can look to the free-scoring Sebastian Tagliabue, who finished the recently concluded Saudi season as top scorer with 25 goals.

The only sides representing United Arab Emirates and Iran, Al Shabab Al Arabi and Esteghlal, meet in Dubai as both sides seek to do their countries proud. Armed with a series of Iranian internationals including Javad Nekonam, Esteghlal start as favourites. However, they will be rightly wary of their hosts' resilience, a key factor in their unlikely progress at the expense of Al Ettifaq and Pakhtakor.

Further east, FC Seoul head to Beijing hoping to continue their form against Chinese sides, having twice defeated Jiangsu during the group phase. A 2-0 victory at Daejeon Citizen on Saturday has provided the visitors with a timely morale-booster, while Beijing will be looking to put a 2-1 defeat at Guangzhou R&F behind them.

Jeonbuk approach the visit of Kashiwa with a score to settle against their Japanese visitors, having lost both away and home last year. Four group stage points against Urawa Red Diamonds in this year’s campaign should, however, give them confidence ahead of another meeting with J.League opposition. Still, the visitors look sure poised to pose a big threat and come into the match boosted by two successive domestic wins.

Marcello Lippi's Guangzhou, meanwhile, travel to Australia targeting an away win against the Mariners. The visitors established a three-point gap at the summit of the Chinese table with Friday's 3-0 triumph at Shanghai Shenhua, with in-form striker Gao Lin twice on target. Graham Arnold's hosts, meanwhile, will be aiming to overcome any psychological damage inflicted by their recent 3-0 home loss to Kashiwa.

Player to watch
Having captained Esteghlal to Iranian league title and through the Champions League group phase, Iran's striking veteran Farhad Mijidi – who fired Al Ain to the inaugural title – will be out for yet more continental glory.

The stat
- A quartet of sides left in the competition – namely, Kashiwa, Al Ahli, Bunyodkor and Jeonbuk - enter the knockout stage undefeated.

What they said
"Against a strong, dangerous rival like FC Seoul, we should maintain our patience. They are good at passing and attacking, so we must counter them with a proper game plan," Beijing Guoan coach Aleksandar Stanojevic.

Round of 16 first-leg fixtures
14 & 15 May
Al Gharafa-Al Shabab
El Jaish-Al Ahli
Al Hilal-Lekhwiya
Al Shabab Al Arabi-Esteghlal
Beijing Guoan-FC Seoul
Buriram United-Bunyodkor
Central Coast Mariners-Guangzhou Evergrande
Jeonbuk Motors-Kashiwa Reysol