Li Weifeng put the K-League side in front in the 44th minute and Eduardo netted a second goal before the interval.

Second-half goals from Hong Soon-hak and Park Hyun-beom set the seal on an impressive Group G victory before Marquinhos netted an injury-time consolation for the visitors.

"Nobody would have predicted that we would win by such a scoreline," Cha said. "Kashima are technically very good both as a team and individually.

"If we had made mistakes in the second half we would have been in for a very difficult time and we have to make sure that we are thoroughly prepared when we go to Japan for the return match."

Kashima boss Oswaldo Oliveira felt the J.League side could still have got something from the game if they had hit back after the interval but admitted they were ultimately outclassed.

"If we could have scored in the second half we could have got a result," he said.

"In football, you can win or lose and today we were poor. We didn't really create chances to score and when Suwon got their first goal, there was a feeling that this was their game."

J.League side Kawasaki Frontale edged out Tianjin Teda 1-0 in Group H's other game.

While it was not a vintage performance, Japan international midfielder Kengo Nakamura was pleased to begin with a win.

"Collecting three points in our home game was our minimum target to achieve and we've done that. That is something we can take heart from," he said.

"But we have to do something about how we cope with situations when our opponents stay deep in their own half. But this is a step forward for us."

Tianjin boss Zuo Shusheng cited a lack of experience on his players' part as a key reason behind their defeat.

"I think our team played well. We attacked well and defended well but the problem was we gave up the goal too early in the game," he said.

"That was because this is our first ACL and we lack experience. We created many chances but couldn't capitalise on them."

Al Ittihad coach Gabriel Calderon was a relieved figure after the two-time Asian champions scored a pair of late goals to record a dramatic 2-1 win over Esteghlal in Group C.

The Jeddah side wasted a number of opportunities but secured all three points as Emad Moteab levelled with three minutes remaining and Hicham Aboucherouane fired home a superb stoppage-time winner.

"My team was successful and the most important thing is that we kept the three points at home. Do not forget that my team was the better side in the match," said Argentinian Calderon.

"There is no need for excuses. We had several scoring chances but we were unlucky not to find the net.

"I just care about the performance of my players and their passion and I am sure they will do better in their next games."

Meanwhile Al Jazira coach Abel Braga rushed to the defence of Fernando Baiano after the Abu Dhabi side's 1-0 loss to Umm Salal of Qatar in another Group C encounter.

Baiano missed a penalty, which proved costly as Bahrain striker Ala'a Hubail scored a breakaway winner for the visitors deep into stoppage-time.

"It was a game we would like to put behind us and get on with the rest of the matches in the competition," said Braga.

"Baiano just didn't have luck on his side. That penalty could have given us victory but things changed badly for us at the end.

"Baiano was devastated but I hope he will get over it soon. He has done enough for us. He has played in 13 league games, six Etisalat Cup and two President's Cup games so it is not fair to criticise him for this one mistake.

"It happens to the best of players around the world."