Urawa Reds and Seongnam Ilhwa Chunma hold slender 2-1 advantages as they visit Jeonbuk Hyundai Motors and Al Karama respectively, while the matches between Kawasaki Frontale and Sepahan, and Al Hilal and Al Karama, are still deadlocked after stalemates last week.

J.League champions Urawa will regret missed opportunities in the first leg against Jeonbuk if they fail to advance to the last four.

The Japanese side completely dominated the defending champions from South Korea at Saitama Stadium and were cruising through goals from Makato Hasebe and Tatsuya Tanaka before veteran defender Choi Jin-cheul grabbed what could ultimately prove to be a valuable away goal just before the final whistle.

It leaves the Korean side needing only a 1-0 win in the second leg at Jeonju World Cup Stadium.

If Jeonbuk do get past the current Japanese league leaders, they would set up an interesting semi-final clash with either K-League rivals Seongnam or Syrian league champions Al Karama, the team that they defeated in last year's final.

Reigning domestic champions Seongnam came from behind to claim a 2-1 win over the Syrian side in their first encounter in Korea.

Senghor Koupouleni struck an early goal for the visitors but two goals in two minutes in the second half from Kim Min-ho and Choi Byung-kuk gave the current K-League leaders a slight advantage for the return match at Khaled Ibn Al Waleed Stadium.

But Al Karama have yet to be beaten at home in the competition, winning seven of their nine matches and their most memorable victory came at the same stage of the competition last year when they recovered from a 2-0 first leg deficit to thrash defending champions Al Ittihad 4-0.

The other two quarter-finals have yet to produce a goal despite some enterprising play in the first-leg matches.

Kawasaki Frontale have struggled of late in the J.League but gave a good account of themselves in Iran last week against Hazfi Cup holders Sepahan.

The Japanese side, who are appearing in the AFC Champions League for the first time, showed plenty of verve in attack and took the game to the home side in Esfahan.

Sepahan have enjoyed a solid start to the Iran Pro League season with four wins and a draw in their opening five games but coach Luka Bonacic will have to find a way to deal with Frontale's pace and swift counter-attacks when the action shifts to Kawasaki Todoroki Stadium if they hope to keep their semi-final hopes alive.

The winners of the Kawasaki-Sepahan tie will face either Al Hilal of Saudi Arabia or Al Wahda from the United Arab Emirates.

The two Arab giants were unable to manage a breakthrough in their first leg with the Saudis hitting the woodwork while Al Wahda had a late effort disallowed for offside.

Both teams will be keen to make up for their previous disappointments in the AFC Champions League.

Al Hilal are in the last eight for the first time after failing to negotiate the group stage in their previous campaigns.

Al Wahda reached the quarter-finals in 2004 but were humbled 5-1 on aggregate by Uzbek side Pakhtakor, and struggled last season as they finished a distant third behind group winners Al Karama and Iranian side Sepahan.

The winners of Wednesday's ties will have little time to rest, however, as the semi-final first-leg games take place on October 3.