West Zone
Wednesday's west-zone matches will decide the first and second-placed sides in Groups A and B.
All four Saudi Arabian clubs, Iranian giants Piroozi, Pakhtakor of Uzbekistan and Umm Salal of Qatar are through to the knockout stage, with the last spot decided by Tuesday's Group D clash between Uzbek champions Bunyodkor and Al Shabab Al Arabi of the UAE.
Al Hilal, the 2007-08 Saudi champions and this season's runners-up, host Pakhtakor at the King Fahd International Stadium in Riyadh to decide Group A's top team, who will earn a home tie next Wednesday against the Group C runners-up.
Hilal are on 11 points, two behind Pakhtakor, after both teams won on matchday five. Hilal beat Saba Battery 1-0 in Iran, while Pakhtakor beat Al Ahli of the UAE 2-0 at home.
The runners-up in Group A face a trip to Dammam next week to face Group D winners Ettifaq.
In Group B, Piroozi host Al Shabab at the Azadi Stadium knowing victory in Tehran would secure the reds top spot due to a better head-to-head record against the Saudi side, after the sides drew 0-0 in Riyadh in March.
Shabab are on seven points, three ahead of Piroozi, after their 1-0 victory over Al Gharafa earlier this month eliminated the back-to-back Qatari champions. A draw or win in Tehran would earn Enzo Trossero's side a home match against the Group D runners-up.
Shabab further boosted their confidence by lifting the King's Cup last Friday, beating new Saudi champions Al Ittihad 4-0 in the final.
The Piroozi-Shabab clash is the only remaining Group B contest following the earlier withdrawal of Sharjah, who lost their first four matches and pulled out before matchday five to focus on avoiding relegation from UAE's top flight. Sharjah's withdrawal rendered all their matches null and void.
AFC Champions League 2009 – Matchday Six; Wednesday, May 20
A Al Ahli (UAE) v Saba Battery (IRN), Al Rashid Stadium, Dubai
A Al Hilal (KSA) v Pakhtakor (UZB), King Fahd International Stadium, Riyadh
B Piroozi (IRN) v Al Shabab (KSA), Azadi Stadium, Tehran
E Beijing Guoan (CHN) v Nagoya Grampus (JPN), Beijing Workers Stadium, Beijing
E Ulsan Hyundai (KOR) v Newcastle Jets (AUS), Ulsan Munsu Football Stadium, Ulsan
F Sriwijaya (IDN) v Shandong Luneng (CHN), Jaka Baring Stadium, Palembang
F Gamba Osaka (JPN) v FC Seoul (KOR), Expo ’70 Stadium, Osaka
(China.org.cn by May 19, 2009)