Japan's Kawasaki Frontale booked their spot in the knockout phase of the Asian Champions League thanks to a 4-0 thrashing of Group G minnows Eastern SC of Hong Kong on Tuesday night.

Brazilian striker Rhayner got the ball rolling with the first on 28 minutes before Shogo Taniguchi's header extended Kawasaki's lead on the stroke of halftime.

Substitute Tatsuya Hasegawa grabbed the third early in the second period before Tatsuki Nara wrapped up the win in the 53rd minute. Frontale finished top of Group G with 10 points ahead of China's Guangzhou Evergrande and will face either J-League rivals Kashima Antlers or Thailand's Muangthong United in the round of 16 later this month.

"Although there was a bit of difference in quality between the two teams today, we knew there was pressure on us to win and qualify from the group," said Frontale coach Toru Oniki, whose team had four draws before winning their last two matches.

"The game really turned for us after getting two goals in the first half, we got the result and I am thankful for the effort my players put in."

Oniki's men became the third Japanese team to make the knockout phase along with Kashima and Urawa Reds, but Gamba Osaka's slim hopes of advancing ended with a 2-0 defeat away to South Korea's Jeju United in Group H.

Japanese champions Kashima play Muangthong at home on Wednesday. Surprise package Muangthong lead Group E with 11 points, two ahead of Antlers. Also on Wednesday, Group F leaders Urawa are away to already eliminated FC Seoul.

Oniki and man of the match Rhayner admitted they would rather avoid playing a Japanese team until the later rounds of the competition.

"I would rather not have an all-Japanese clash at this early stage of the competition so I guess it would be the Thai team," said a smiling Oniki.

Rhayner said: "I would rather play the Thais too. We don't want Japanese teams playing each other yet. We would rather be able to show our quality in Asia and play a Japanese team later in the competition. We can play Kashima in the J-League anyway."

At Todoroki Stadium, Frontale dominated from the outset without seriously threatening, but they suffered a blow on 20 minutes when striker Yu Kobayashi limped off injured and was replaced by Hasegawa.

But despite the loss of their captain, the home side eventually capitalized on their possession to go in front, Shintaro Kurumaya dragging back a cross from the byline for Rhayner to score with a free header.

Further chances went begging before Frontale doubled their lead, Taniguchi getting on the end of Kengo Nakamura's corner to score with a towering header in off the left-hand post.

Rhayner gift-wrapped the third for Hasegawa, the substitute tapping in at the far post in the 49th minute before Nara headed home another Nakamura corner soon after to round off the scoring.

Eastern finished their debut ACL campaign with just one point but their female coach Chan Yuen Ting said she was proud of her players.

"I am satisfied with the performance of my players especially in this game as we used some players that didn't play a lot in Hong Kong," she said. "They were outstanding and made a lot of effort and followed the defending plan. Even though we made some mistakes we didn't deserve to concede four goals."

"But football is like this. I think that we learned a lot in these six games and we will keep improving in the future."

Frontale on the eve of the game urged their fans to not fly a controversial wartime flag that landed the club in hot water with the Asian Football Confederation.

Kawasaki were fined $15,000 and placed on one-year probation by the AFC last Thursday after two spectators raised the 16-ray rising sun flag on April 25 during a 1-0 away win to South Korea's Suwon Bluewings.

Kawasaki carried out security checks for the flag and other potentially controversial symbols prior to kickoff at Todoroki.

The AFC said Kawasaki would automatically be forced to play one game behind closed doors and be subject to more severe punishment if the flag reappears during their probationary period.

Kawasaki maintained the flag, used by the Imperial Japanese Army during World War II and still flown by the Japanese Maritime Self-Defense Force, carries no political or discriminatory intent. The view was shared by the J-League and the Japan Football Association.

The flag is considered a symbol of Japan's wartime aggression in many Asian countries, including South Korea and China.