Bunyodkor had made the ideal start at Jar Stadium as Jovlon Ibrokhimov struck his first goal in eight AFC Champions League appearances this season after just five minutes.

But after Brazilian striker Rafinha (Rafael dos Santos de Oliveira) levelled the contest before half-time, second-half headers from Ulsan's Korea international duo Kim Shin-wook and Le Keun-ho turned the contest quickly in favour of the K-League side.

Jasur Khasanov was handed an opportunity to make Bunyodkor's task next week in Korea easier after Kang Min-soo was adjudged to have handled the ball inside the penalty area with 14 minutes remaining, but the Uzbekistan international hit the post from 12 yards.

"I did not expect such a big defeat. I did not expect we would lose as we started very well and we had our chances," said Kasimov.

"But we handed the win to Ulsan as we made a lot of mistakes. We made many mistakes in defence.

"For the first goal we made three mistakes in a row and Ulsan have very good strikers who can capitalise on these mistakes. They had their chances and they won."

Unlike Ulsan, Bunyodkor do not have to contend with a domestic fixture before the second leg next Wednesday at Ulsan Munsu Stadium as Kasimov's side seek to complete a seemingly unlikely comeback to ensure next month's final takes place in Tashkent.

"We now don't have any more chances, we will do our best in the second leg to recover," added Kasimov.

"It will be a tough game in Korea but we must remember this is our chance to reach the final and we must have no regrets. We must do our best."