Coolen feels Adelaide United were unlucky not to beat league leaders
The Reds had their chances against the league leaders but failed to put them away, allowing the Championship favourites to score the required winner just over 20 minutes from time through Jean Carlos Solorzano.
But Coolen was adamant that his team deserved more than a defeat if only they could do better with their final ball into the area.
"We did well in the first half, we stopped them playing football," Coolen said.
"The way I saw it we were the better team. We had good transition moments, only the last pass or the last run or the last shot was not good enough, but we stopped them playing football the way they prefer in the first half.
"If you don't play a terrific game, which they didn't do, and still score in one chance a nice goal, it also says that you're a good team, so we did everything we could today but it wasn't enough.
"A lot of things we did well, the only thing missing was the last touch should be a better decision and should create some more chances, that was the only thing, and it's a real important thing, that we didn't do well today."
The Reds will be able to atone for their fourth loss in five matches when they arch rivals Melbourne Victory at AAMI Park on Sunday, 9 January.