Adelaide United coach Aurelio Vidmar was left ruing the slow performance of his team against Sanfrecce Hiroshima in the Asian Champions League last night.

The Reds dropped their first points in four group stage matches when they were defeated 1-0 by the J-League club despite having more clear cut chances.

Vidmar said it was the lack of intensity of his players to push forward that caused their demise and admitted his side were lacklustre throughout most of the 90 minutes.

"We probably didn't get forward as quickly as we would have liked," Vidmar said.

"Every time we won the ball in the midfield our first decision was to go back and they got numbers behind the ball pretty quickly, and then our movement going forward was pretty lacklustre in the first half.

"We came here with intentions to win the game. We thought we could have created a number of chances throughout the course of the game, but because our movement going forward was a little bit slow, they got numbers back very quickly and when that happened we found it very difficult to penetrate.

"I don't think that we were totally under pressure, although they had a few shots at goal and a chance that hit the bar (in the first half), we seemed to be reasonably in control and then obviously that goal right on half time hurt us," Vidmar added.

"The quality of our passing was not up to scratch, but I thought in the second half we came out and worked very hard, we changed the formation a little bit, put them under more pressure and then some gaps started to appear for us…but it just wasn't our night unfortunately."

Despite the loss, the Reds remain on top of the Group H table on goal difference to reigning champions Pohang Steelers who they meet on Match Day 5 in Korea on April 13.