Japanese giants Kashima Antlers host Korea's Suwon Bluewings on Tuesday in a vital Group G encounter in the penultimate round of matches in the AFC Champions League group stage.
Kashima, who have won the last two editions of the J.League, and reigning K-League champions Suwon are level on nine points after four matches.
The pair are three points ahead of Shanghai Shenhua, although the Chinese side are strong favourites to win their away encounter against Singapore Armed Forces (SAF), who have yet to pick up a point.
Kashima are arguably under the most pressure to win, as their final match is away to Shanghai. Suwon, who beat Kashima 4-1 at home in their opening match in March, will host SAF in their last match, so will be confident of picking up three more points on the final day.
The Antlers go into the match high on confidence and on top of the J.League after beating JEF United Chiba 2-0 away on Saturday with goals from midfielders Takuya Nozawa and Mitsuo Ogasawara.
Since losing to Suwon, Oswaldo de Oliveira's charges have won their last three AFC Champions League encounters, beating Shanghai 2-0 at home in late March and recording two comfortable wins over SAF in April.
Suwon, in contrast, are having a poor domestic season and their chances of retaining their K-League title look slim, as they currently lie third from bottom with only one win in eight matches.
The Bluewings, however, have an excellent continental record, having won the old Asian Club Championship in 2001 and 2002, and Cha Bum-kun's side would virtually secure top spot in the group if they can beat Kashima.
Group H leaders Kawasaki Frontale, who have 10 points, travel to China to face Tianjin Teda, who have only an outside chance of making the top two after picking up only two points so far.
Kawasaki are one of only three unbeaten teams in the east zone, along with fellow Japanese sides Nagoya Grampus (Group E) and reigning champions Gamba Osaka (Group F).
Korea's Pohang Steelers have six points and could also secure their top-two place in Group H with victory over Australia's Central Coast Mariners, who have two points.
In Group F, third-placed FC Seoul play their home match against bottom-placed Sriwijaya on Tuesday, a day ahead of the group's other encounter between Chinese champions Shandong Luneng and Gamba, who top the group with 12 points.
Seoul, second in last year's K-League and lying third in the current campaign, have four points and need to beat the Indonesian champions to have a chance of overtaking Shandong, who are on seven.
In the west zone, Group C leaders Al Ittihad can secure a top-two placing with an away win against bottom-placed Esteghlal at the Azadi Stadium.
Ittihad, who were recently crowned as Saudi Arabian champions for the 2008-09 season, have eight points, while Esteghlal, recently crowned winners of the Iran Pro League, have two.
Umm Salal are second in the group with seven points and the Qatari club will seek a home victory against Al Jazira of the UAE, who have three points, to secure their place in the round of 16.
Group D features a key clash between Saudi Arabia's Ettifaq and Uzbek giants Bunyodkor, as both teams seek to secure top place and a home tie in the round of 16. Ettifaq have nine points, two more than Bunyodkor, and will seek to avenge their 2-1 away defeat to last year's semi-finalists in March.
Sepahan, the 2007 runners-up, have four points and would still be in with a chance if they could secure an away victory on Tuesday against 2007-08 UAE champions Al Shabab Al Arabi, who are on three.
Matchday six features games on May 19 and 20. The top-placed team in each of the eight groups will enjoy home advantage against one of the second-placed sides in the one-leg round of 16, which will be held in the west zone on May 27 and in the east zone on June 24.
AFC Champions League 2009 – Matchday Five
May 5, 2009
Group C
Esteghlal (IRN) v Al Ittihad (KSA), Azadi Stadium, Tehran
Umm Salal (QAT) v Al Jazira (UAE), Qatar Sports Club, Doha
Group D
Al Shabab Al Arabi (UAE) v Sepahan (IRN), Al Maktoum Stadium, Dubai
Ettifaq (KSA) v Bunyodkor (UZB), Prince Mohamed bin Fahd Stadium, Dammam
Group F
FC Seoul (KOR) v Sriwijaya (IDN), Seoul World Cup Stadium
Group G
Kashima Antlers (JPN) v Suwon Bluewings (KOR), Kashima Soccer Stadium
Singapore Armed Forces (SIN) v Shanghai Shenhua (CHN), Jalan Besar Stadium
Group H
Tianjin Teda (CHN) v Kawasaki Frontale (JPN), Tianjin Teda Stadium
Pohang Steelers (KOR) v Central Coast Mariners (AUS), Steelyard Stadium, Pohang
Groups A, B, E and F (one match) play Matchday Five on Wednesday, May 6.
(AFC May 5, 2009)