The Reds were leading 1-0, thanks to Hajime Hosogai's low strike after 22 minutes, with nine minutes remaining in the all-J.League tie when Al Hilali made the decision to award a spot-kick after Ryuji Bando went down rather easily in the box under pressure from Takahito Soma.

The Omani official had no hesitation in pointing to the spot, with Yasuhito Endo tucking away the chance to leave the tie poised at 1-1.

Engels, however, feels his side should be holding an advantage going into their home second-leg tie at Saitama Stadium.

"I think it wasn't a penalty but this is not the point, the point is the referee didn't see it," he said.

"He didn't see the situation, that is the point, but our players said he dived. It's a penalty and we cannot change it but the point is the referee didn't see it.

"If you would've asked me before the game, 1-1 is okay but we were leading and we had a few chances in the first half so it is not okay. But I think we should be satisfied with this result."

Despite his frustration Engels was content with the performance of his defence, who were without the injured Marcus Tulio Tanaka, as they stood firm in the face of some sustained pressure in the second half before Endo's penalty.

"I was pleased with how we defended, especially in the second half," he added.

"In the first half we were more attacking, we were well organised, but in the second half it was more of a fight, organisation with fight, and that was good to see.

"They only got a goal from a penalty, that's why I cannot say anything about the defence. I cannot say anything bad about our defensive line but we can improve our defending as a team.

"We shouldn't retreat so fast, we should start to defend from the front and we can improve on that I think."

A goalless draw in the second leg would be enough for the Reds to qualify for the final, however, Engels revealed his side would look to attack.

"I think we should approach the second game like the first half, try to be a little bit more aggressive up front as we cannot stay back and wait for a 0-0 draw," he concluded.

"We need to play to keep the ball. The best way to defend is to have the ball and that's the key point for the next game."