The group campaign of the 2012 AFC Champions League reaches the penultimate matchday this week with a series of favourites expecting to seal early progression and join Al Jazira in the Round of 16.

In west Asia, two-time champions Al Ittihad and Saudi compatriots Al Ahli are on the verge of qualification and the same can be said of Iran's Sepahan and Persepolis. In the continent's east, FC Tokyo, Ulsan Hyundai and Adelaide can all progress with a single point while a home win over Jeonbuk Motors will see Chinese debutants Guangzhou Evergrande also through. Join as we preview the enticing showdowns across Asia.

The match
Persepolis - Al Hilal
Given the two sides' legendary status on both the home and continental stage, Group D's top-of-the-standing meeting looks set to capture the most attention. Both teams are among the most successful in their respective leagues, with Persepolis the nine-time Iranian champions while Al Hilal have prevailed in the Saudi championship a record 13 times. Adding to their unrivalled domestic achievements, the Riyadh giants have secured continental silverware on four occasions with two Asian Club Championships and two Asian Cup Winners’ Cup titles, while the Iranians lifted the Asian Cup Winners’ Cup in 1991.

Both have not been firing on all cylinders on the local front this season, with Al Hilal conceding the league title to Al Shabab after finishing third, while Persepolis are languishing in 11th following a recent 4-1 defeat at Teraktor-Sazi. However, the Tehran club have impressed in Asia this year, enjoying a two-point lead ahead over Al Hilal with a draw enough to see them through. The home side will look to the scoring-form of Libyan striker Eamon Zayed and captain Ali Karimi with each having scored three times to date. The visitors, for their part, will count on their Moroccan striking-ace Youssef El Arabi. Qatar’s Al Gharafa, meanwhile, face a must-win scenario against bottom side Al Shabab if they are to maintain their ambitions.

The other attractions
With the already-qualified Al Jazira welcoming bottom side Nasaf, runners-up Al Rayyan face a straightforward scenario in Group A with a win at Esteghlal enough to seal them the second qualifying spot. The home side enter the re-match looking to build on their first-leg 1-0 win, but the visitors can take heart from their recent showing after edging Al Sadd on penalties to win their fourth Heir Apparent Cup.

In Group B, runaway leaders Al Ittihad can progress with a draw at Pakhtakor, who shared the spoils with Lokomotiv in a 1-1 draw in their recent domestic fixture. Should the Tashkent giants lose, the result will benefit third-placed Bani Yas who can leapfrog to second with a victory over pointless Al Arabi.

Sharing Group C's top place with seven points each, Al Ahli and Sepahan can jointly progress from their pool with victories over Lekhwiya and bottom side Al Nasr respectively. Boosted by their runners-up finish in the Saudi league, Al Ahli will aim to avenge the 1-0 first-leg loss to Lekhwiya, who recently retained the Qatari championship. Sepahan, for their part, arrive at Al Nasr on the back of a 2-0 win over Shahin which saw them maintain a three-point lead and edge closer to the Iranian league title.

At the top of Group E with a three-point cushion, Adelaide United will make it through with a home draw against Bunyodkor. The section's other game pits Pohang Steelers against surprise strugglers Gamba Osaka, who continued their miserable form this season by conceding five unanswered goals at Kashima Antlers on Saturday.

Group F joint leaders FC Tokyo and Ulsan Hyundai can each progress with a draw against strugglers Brisbane Roar and Beijing Guoan, both of whom have salvaged just two points from four games. The Japanese capital club must remain wary of the visiting Roar who recently edged Perth Glory to become the first team to win back-to-back A-League championships.

Group G has proved to be the most open, with all four teams maintaining varying degrees of hope. Level on six points at the top, Seongnam Ilhwa and Nagoya Grampus enter their contest in the knowledge that the winning side will progress, although both will need to push aside 2-1 defeats against Urawa Red Diamonds and Suwon Bluewings in their respective league fixtures. Central Coast Mariners and Tianjin Teda will be both in desperate need for all three points when they meet in Australia.

Guangzhou can seal Group H's first qualifying spot if they beat Jeonbuk, regardless of the other result. A solitary-goal win at Tianjin over the weekend is all the Chinese debutants need going into the crucial match. Despite stunning the Korean champions 5-1 in the opener, Jeonbuk have since enjoyed a return to form, having come up with back-to-back defeats over Buriram before recording a spirited 5-2 home triumph over Gwangju FC.

Player to watch
Argentinian playmaker Dario Conca was instrumental with two goals and one assist as Guangzhou thrashed Jeonbuk in their first meeting. Having sat out of Friday's Tianjin game, the 28-year-old enters the re-match seeking to build on his recent form.

The stat
- The number of goals scored by Persepolis to date with the Iranians the tournament's most prolific side.

What they said
"I've been at the club for seven years, I've been here right from day one and we've been through a lot. We have a very successful style in the A-League. Now we need to find a successful style in the Asian league so that will be our next step forward" Newly-appointed Brisbane Roar coach Rado Vidosic

AFC Champions League Matchday 5 fixtures 
1-2 May
Group A: Al Jazira-Nasaf, Esteghlal-Al Rayyan
Group B: Al Arabi-Bani Yas, Pakhtakor-Al Ittihad
Group C: Al Ahli-Lekhwiya, Al Nasr-Sepahan
Group D: Persepolis-Al Hilal, Al Gharafa-Al Shabab
Group E: Adelaide United-Bunyodkor, Pohang Steelers-Gamba Osaka
Group F: FC Tokyo-Brisbane Roar, Beijing Guoan-Ulsan Hyundai
Group G: Seongnam Ilhwa-Nagoya Grampus, Central Coast Mariners-Tianjin Teda
Group H: Guangzhou Evergrande-Jeonbuk Motors, Kashiwa Reysol-Buriram United