GUANGZHOU - Super-rich Chinese club Guangzhou Evergrande are facing the toughest challenge this season with Dario Conca and Muriqui set to miss the crucial fixture against Thai league champions Buriram United in AFC Champions group stage.

Conca, banned for nine matches and fined a league record 1 million yuan($159,000) for complaining on his micro-blog about being replaced early in the match against Jeonbuk two weeks ago.

"Why it's always me replaced early in the match. I am in good condition," the Argentine said on his micro-blog after the team lost to Joenbuk 3-1 that night.

"I'am eager to go back to the field. I am always ready to play for the team," said the 29-year old Argentine before the team left Guangzhou for the Thai capital of Bangkok on Tuesday.

Tuesday's match will be crucial for the Chinese super league champions as they must win to guarantee a place in the final 16.

Conca's appearance seems unlikely as the club Owner Xu Jiayin said it was utmost important to protect the authority of head coach Lee Jang-soo.

The discord between the South Korean coach and the Argentine, however, has deepened since last season.

"He doesn't talk much with the coaching team. He didn't speak a word to Lee over four months," said a club top official who required anonymity.

Lee, who guided the team to top flight in 2011 and won the title with a margin of 15 points in the table, is now facing a must-win match in Burriram.

Conca's absence is not his last misfortune as Brizilian striker Muriqui suffered a leg injury that needs at least three weeks' recovery.

Conca, Muriqui and Cleo combined for 11 goals in AFC champions league for the Guangzhou side, which hasn't experienced a single match without any two of them before.

Fortunately, they have a healthy Cleo, who scored the equalizer in their home match against Burriram.

"We know it is a vital match, and without Conca and Muriqui, it will be tougher. So I must take the responsibility," said the 26-year old Brazilian.

But Cleo knew his position would no longer be steady since the club announced the signing of Dortumond striker Lucas Barrios two weeks ago.

A depleted Guangzhou are facing an even tougher Buriram.

"The experience from the last five matches has taught us how to play to move to the next stage," said Buriram owner Newin Chidchob.