Jeonbuk, who won the 2006 AFC Champions League and last year's K-League, booked a place in Sunday's one-leg semifinal away at Jeju United and also secured Korea's last spot in the 2011 AFC Champions League.

FC Seoul and Jeju automatically qualified for next year's AFC Champions League by finishing first and second in the K-League table earlier this month, with Seoul proceeding straight to the two-leg final of the playoffs.

Suwon Bluewings were the first Korean club to qualify for the AFC Champions League by winning the FA Cup last month.

Defender Cho Sung-hwan headed home in the 22nd minute as Jeonbuk beat Seongnam at the Jeonju World Cup Stadium on Wednesday night, in a match-up of the finalists from last year's playoffs.

Cho was also on target last Saturday when he and Brazilian attacker Eninho scored in the 2-0 win over Gyeongnam 2-0 in the first round.

K-League clubs dominated this year's AFC Champions League with a record four clubs in the quarterfinals - Seongnam, Jeonbuk, Suwon and 2009 winners Pohang Steelers. Seongnam were crowned Asian club champions for a second time after beating Iranian club Zobahan 3-1 in the final in Tokyo on Nov. 13.

Six of this year's quarterfinalists will return for next year's AFC Champions League - Zobahan, semifinalists Al-Hilal and Al-Shabab of Saudi Arabia and quarterfinalists Jeonbuk, Suwon and Qatari champions Al-Gharafa.

So far, 27 places among the 32 teams for next year's group stage have been filled.

In Japan, Nagoya Grampus qualified for their second AFC Champions League in three years by securing their first J.League title last Saturday. The second and third league places are still to be confirmed, while the winners of the Emperor's Cup final on January 1 will book Japan's fourth and final spot in Asia.

The last two spots in the group stage, which kicks off on March 1, are reserved for the winners of the east and west playoffs in mid-February.

At least 15 clubs from this year's AFC Champions League will return for the 2011 campaign and that figure could rise if Kashima Antlers, Gamba Osaka or Kawasaki Frontale qualifies from Japan, and if Al Ain of the UAE or Al Sadd of Qatar progress from the west-zone playoffs.

The draw for the group stage of the 2011 AFC Champions League takes place on Dec. 7 at Hilton Petaling Jaya in Kuala Lumpur.