For the first time since the inception of the tournament in 2003, Japan will be represented in the knockout stage with highly-fancied Urawa Reds meeting defending champions Jeonbuk Hyundai Motors of Korea, while Kawasaki Frontale face a daunting visit to Iran to take on Hazfi Cup holders Sepahan.

Last season's runners-up Al Karama of Syria return to Korea to play K-League champions Seongnam Ilhwa Chunma, while Al Wahda of the United Arab Emirates take on Al Hilal of Saudi Arabia in a clash between two of the top sides in the Middle East.

The winners of the competition will not only earn the right to be called Asia's top club but will also qualify for the FIFA Club World Cup in Japan in December.

Having earned a bye through the group stage following their victory in last year's tournament, Jeonbuk begin the defence of their title with a tricky trip to Saitama to take on Japanese double winners Urawa in the first leg of their quarter-final tie.

Few rated the Korean side's chances in the competition last year but despite finishing with one of the worst records in the K-League, they were crowned Asian champions after a memorable run that included victories over the league champions of China, Japan and Korea before a dramatic 3-2 aggregate win against Al Karama in the final.

Jeonbuk's domestic form has improved this season with Choi Kang-hee's side finding themselves handily placed in fifth spot and in contention for a spot in the K-League championship play-off at the end of the regular season.

But defending their continental crown will not be easy against a Reds side that currently holds a four-point lead in the J.League after last weekend's 4-2 away victory over Sanfrecce Hiroshima.

Urawa were unbeaten during the group stage of this year's Champions League although their performance was far from impressive as they drew four of their six games and only narrowly edged out Sydney FC of Australia by a point.

However, the Japanese side are still likely to give Jeonbuk a torrid time at Saitama Stadium, where they enjoy the backing of perhaps the most passionate club supporters in Asia.

If Jeonbuk do prevail, they would set up either an all-Korean semi-final clash with Seongnam or a re-match of last year's final against Al Karama.

The Syrian side were also surprise finalists last year but proved that they were no one-year wonders in 2007, successfully defending their Syrian league title and topping their AFC Champions League first round group to book their spot in the knockout stage for a second year in a row.

The home form of Mohamed Kwid's side has been the key to their success so far in the competition with Al Karama winning seven and drawing two of their previous nine matches at Khaled Ibn Al Waleed Stadium.

But away from Home, they have not been nearly as effective, winning only three matches and losing five times.

And they can expect few favours from their hosts on Wednesday as current K-League leaders Seongnam attempt to make amends for the debacle of 2004 when they blew their opportunity of lifting the AFC Champions League title after losing 5-0 at home to Al Ittihad of Saudi Arabia in the second leg of the final

Kim Hak-bum's side booked their place in the last eight after trouncing Shandong Luneng 3-0 in their final group game to leapfrog past the Chinese champions.

In Abu Dhabi, Al Wahda take on Al Hilal in a encounter between two clubs eager for silverware after finishing runners-up in their respective leagues in the 2006/07 season.

For Al Wahda, who finished four points behind Al Wasl last season, it is an opportunity to finally emerge from the shadows of league rivals Al Ain, the inaugural winners of the AFC Champions League in 2003.

It is their second appearance in the last eight following their quarter-final defeat to Pakhtakor in 2004 and the Abu Dhabi side will be looking for a better outcome after winning four of their first five games during the group stage to secure qualification for the knockout stage with a game to spare.

While Al Wahda have secured a spot in the 2008 AFC Champions League, due to Al Wasl claiming the double in UAE, Al Hilal have to win the tournament to book a spot in next year's competition after losing the Saudi championship play-off to arch-rivals Al Ittihad.

The Riyadh giants have two Asian Club Championships, two Asian Cup Winners' Cups and two Asian Super Cups to their name but this year's competition marks the first time that they have even got beyond the group stage.

But with a strong line-up that includes Saudi international captain Yasser Al Qahtani and playmaker Mohammed Al Shlhoub, Al Hilal are amongst the favourites for this year's title.

The final quarter-final match presents an intriguing clash in Esfahan between the two teams that have never previously got this far in the competition.

For Sepahan, it is a case of third time lucky after the Iranian side narrowly missed out on the quarter-finals in 2004 and 2005. They safely negotiated it this time with a series of impressive performances during the group stage, including a 5-0 trouncing of Syria's Al Ittihad in their penultimate match.

Sepahan have not been beaten at home in their previous nine Champions League games at Foolad Shahr Stadium and a good home win against Kawasaki in the first leg is likely to be the key to their progress to the last four.

Taking part in the AFC Champions League for the first time, Kawasaki easily topped their first round group with five wins and a draw.

But Takashi Sekizuka's side will want to arrest an alarming slide in form that has seen them win only three of their last 13 J.League match to slip to mid-table, 19 points behind front-runners Urawa.

The return matches for all of the quarter-finals take place on September 26.