Gamba are coming off the back of a thrilling 4-3 win against Chunnam Dragons in their previous Group G outing and Merrick knows the first goal will be crucial against their J.League opponents.

"I think we have to play a high intensity game, that's our style of football," he said.

"We have to be relentless and keep at them and we've got to score goals. And if we score one, I want to score another.

"Sometimes you have to wait for the right opportunity but the ball must be moving quickly at the same time.

"I guess there's patience from the point of view that we don't have to score in the first minute but the sooner we score the better. We need to build on that."

Victory sit third in Group G, one point behind joint leaders Gamba and Chonburi.

Striker Archie Thompson is out with a knee injury while midfielder Carlos Hernandez also remains on the sidelines.

Akira Nishino's Gamba go into the game on the back of three J.League matches in seven days and the coach admits fatigue has taken its toll on his squad.

"We have had a very tight schedule for the matches domestically in Japan," said Nishino.

"Also we had a very challenging game in Korea for the ACL. On top of that we've had to travel from Japan. To be honest with you, I'm not regarding our team's condition as the best."

Gamba are sweating on the fitness of forward Ryuji Bando (ankle) while defender Akira Kaji is definitely out with a leg injury.

Chonburi face a Chunnam Dragons side desperate to kick-start their continental campaign.

Chunnam coach Park Hang-seo has seen his team slip to defeats in each of their opening two games and the Korean FA Cup holders are bottom of Group G.

But the coach insists a berth in the last eight remains a possibility.

"We haven't given up yet as we can still achieve our goal of reaching the quarter-finals," said Park.

"We have been on the receiving end of a number of defeats recently but we haven't played as badly as the results suggest. Some of the performances have given me hope for the future.

"But we need to be at our best on Wednesday. Chonburi have shown that they are a good team and we are expecting a very tough match."

Strike duo Schuba and Sandro Hiroshi are both injured for Chunnam while captain Kwak Tae-hwi is a doubt with an ankle injury.

Thai champions Chonburi have impressed on their Champions League debut and moved top of the group on goal difference with a 3-1 home win over Melbourne last time out.

However, they will be without suspended midfielder Arthit Sunthornpit while defender Surat Sukha is sidelined by injury.

"We are ready for our match against Chunnam Dragons," team manager Annop Singtothong revealed.

"I believe that we will have a difficult game because Chunnam have lost two matches and they need a result in order to qualify for the next stage. But we are looking forward to the match."