Maurice Steijn blamed missed chances for Al Wahda's exit from the Asian Champions League on Monday night.
The second leg 3-2 loss at the Al Nahyan Stadium saw the Abu Dhabi club beaten 4-3 on aggregate by Saudi Arabia side Al Nassr.
Wahda were the UAE's last hope of success in the competition after Al Ain and Al Wasl succumbed in the group stages and Steijn was frustrated that his side had failed to reach the quarter-finals.
“The biggest difference was that they scored from three or four chances, and we got six to seven chances and scored only two,” said the Dutchman at the post-match news conference.
It had looked good for Wahda when Mohammed Al Menhali had put them ahead on Monday, and on aggregate, with a goal in the 27th minutes.
But Nassr struck twice just before half time, courtesy of Abderazzak Hamdallah and the Brazilian Giuliano, to take control of proceedings.
Giuliano added a third in the 62nd minute to leave Wahda needing to score three times in the final 28 minutes to get through.
Sebastian Tagliabue pulled one back with 11 minutes to go, but that was all Wahda could muster as Nassr move on to the last eight.
Steihn believed that the game could have been different if Nassr goalkeeper Brad Jones had seen red for a foul on Tagliabue in the 65th minute, with the Singapore referee Muhammad Taqi only cautioning the Australian for the incident.
“He was given a yellow card instead of a red,” said the Wahda manager. “For me, the action of the goalkeeper was very clear because he didn’t go for the ball. His action deserved a red card.
“It was important for us because we could have had the numerical advantage with more than 25 minutes left in the game."
Steijn, who took over as Wahda manager in the summer from Henk ten Cate, said he would look to take positives from the loss into the domestic season, that begins on August 23 when they host Fujairah in the Arabian Gulf Cup.
“I can’t blame the players because they did everything they could do," he added. "As a team, we were fighting until the last and if we can play like as we did tonight, we can win many games. We were very unlucky on the night.”
Nassr manager Rui Vitoria was satisfied with the result and how his side had executed their tactics in Abu Dhabi after drawing the first leg.
“We had to win this game to qualify for the last eight and we achieved the result we wanted,” said the Portuguese.
“It was a tough game but we were confident. We are looking forward for the remainder of the competition.”
