Calisto is without a number of key players including striker Teerasil Dangda and former Fulham defender Zesh Rehman for the game at Kuwait SC Stadium.

"We came to Kuwait to play a big game and achieve a positive result but I would like to make clear to everyone that our preparations for this match were not ideal," said former Vietnam manager Calisto.

"We will be missing the best striker in Thailand, Tarassel Dangda, who scored two goals against Oman and Australia in World Cup qualifiers, and defender Zesh Rehman, in addition to our first-choice goalkeeper.

"To miss the three elements essential to your team for a long time is clearly not ideal and we face very high temperatures here in Kuwait."

Kuwait SC manager Dragan Talajic believes home advantage will prove telling for his side.

"I know my team well, and I am always confident that we will win when the match is at our ground, even if the opponent is Barcelona," said Talajic.

"This does not mean that I do not respect the opponents. Quite the contrary, I have respect for the Portuguese coach Henrique Calisto and Thai football in general."

Talajic is also confident the loss of defenders Fahad Awad and Khalid Shammari to injury will not affect the outcome of the game.

"I will not cry about the absence of this or that player because crying will not help and instead of crying, I should focus on finding a suitable replacement for the player," he added.

Nasaf, who found the back of the net 30 times in six games in winning Group A, have their sights set on an eighth consecutive victory in this season's competition when they visit Chonburi.

"Of course we want to win the game, even a tough away match like this," said boss Anatoliy Demianenko.

"Only after some time will we be able to judge our performance but we won every match in the group stage and our aim is to reach the AFC Cup final.

"We have three Uzbek national team players, three Olympic squad players and one Latvian international on our team. We are more than ready."

Chonburi boss Withaya Laohakul knows the importance of building a healthy advantage ahead of the return game in Uzbekistan in two weeks' time.

"Of course we want to win but I would hope we can leave Chonburi with at least a three-goal advantage," he said.

"At this level of competition, to win by one goal is not enough."

Al Wehdat strengthened their squad over the summer, bringing in both Abdullah and Amer Deeb as well as captain and defender Bashar Bani Yaseen although they lost striker Rafat Ali, who joined Kuwait SC.

Boss Mohammed Kwid, though, is focusing on defence when they entertain Duhok at King Abdullah International Stadium.

"It is an important thing to score but more important than that is not to have anyone score in our goal," he said.

Duhok boss Akram Salman, meanwhile, is enjoying the Iraq side's first foray into Asian competition.

"This is the first time the team has played in Asian competition and getting to the quarter-finals is an accomplishment in itself," he said.

"We look forward to keeping the journey going through the players' will to do so. We have passed through tough situations in the past and were able to overcome them."

Finally, Persipura Jayapura host Arbil at Mandala Stadium.

"I've been scouting Arbil since July and I keep myself updated about them everyday. There's never a day gone by without me thinking about how to deal with them," said Persipura boss Jacksen Tiago.

"I think we've got sufficient information about them and we practise everyday how to play them."

Arbil boss Ayoub Odisho, meanwhile, was concerned about Persipura forward Boaz Salossa and midfielder Zah Rahan.

"Their most dangerous players are Boaz Salossa and Zah Rahan. Salossa is very tricky and composed in the penalty box. He will shoot any time he has the chance. He will be difficult to mark," said Odisho.

"Meanwhile Zah Rahan is their playmaker, he controls the rhythm of the game and pull the strings behind the strikers. We have to watch them closely."