Western Sydney Wanderers are looking to continue their fairytale run in their maiden AFC Champions League campaign after stunning Chinese giants and defending champions Guangzhou Evergrande in the quarter-finals.

The Australian side, formed just two years ago, travel to last year's runners-up FC Seoul for the first leg of their semi-final on Wednesday.

Wanderers have been the surprise package of this year's tournament, beating former Asian champions Ulsan Hyundai of South Korea and Japanese champions Sanfrecce Hiroshima en route to the quarter-final against Guangzhou.

Despite their progress, Western Sydney were not expected to get past the star-studded Chinese side who were rated strong favourites to become the first team since Al Ittihad of Saudi Arabia in 2005 to retain the title.

However, after winning 1-0 at home in the first leg, they held on for a 2-1 defeat in China to take the tie on away goals and become only the second Australian club after Adelaide United in 2008 to reach the last four of Asia's Champions League.

Three players who picked up bookings in China will miss the first leg against FC Seoul. Star striker Tomi Juric will sit out, along with Shannon Cole and Brendan Santalab.

Wanderers' face an FC Seoul side hungry for success after they lost on away goals to Guangzhou in last year's final but they will be without three players who miss because of suspension.

Star striker Tomi Juric misses the first leg along with Shannon Cole and Brendan Santalab after they were booked in the quarter-finals.

FC Seoul defeated South Korean rivals Pohang Steelers in a penalty shootout in the quarter-finals and are on a fine run, having gone 10 matches unbeaten in all competitions while Western Sydney are yet to begin their A-League season.

The return leg will be in Sydney on October 1.

The other semi-final features two of the leading clubs in the Arabian Peninsula - Al Hilal of Saudi Arabia, who won the old Asian Club Championship in 1991, and Al Ain of the United Arab Emirates - in what promises to be an intriguing battle between teams who have reached the last four in contrasting fashion.

Al Ain, the winners of the inaugural AFC Champions League in 2003, have been in fine form this season and they romped to a 5-1 aggregate triumph over Al Ittihad in the quarter-finals.

But while the UAE side have bagged 23 goals and scored in every game they have played, they could find it tough to find a way past the stingy Al Hilal defence that has not conceded in their last seven games and ground out a 1-0 aggregate victory over Qatar's Al Sadd in the quarter-finals.

The teams meet in Riyadh on Tuesday with the second leg in Al Ain on September 30.