Marcel Koller felt his Austria players were struck down by nerves as they fell to a shock 2-0 defeat to Hungary to open their Euro 2016 campaign.
Austria started as favourites for the Group F meeting in Bordeaux, but failed to take the lead when on top in the first half, David Alaba unfortunate to see a first-minute effort hit the post.
And they were made to pay in the second period as goals from Adam Szalai and Zoltan Stieber, either side of Aleksandar Dragovic's red card, meant for a miserable opener for 10-man Austria.
"It was a good start to the match; some good combination play," said Koller. "But the more the match went on the more nervous we got, and we let the Hungarians in.
"We were playing against a good Hungarian team that took advantage of this and then we had the red card which made things even more difficult for us.
"I think we started well, with Alaba's long shot, and then one or two nice pieces of combination play. Essentially I think we were too nervous in the first half and lost the ball too often unnecessarily.
"We conceded the goal and then Dragovic was sent off, which didn't help us. Then the second counter made it 2-0, which was also unnecessary. It's happened now, though. The nervousness is tough to judge."
Austria - who dropped just two points in 10 qualifying matches - face Portugal and then Iceland in their final two group games, facing an uphill struggle to reach the last 16.
But Koller remains optimistic his side can gain the results they need to advance to the second round.
"It's going to be a tight group. The situation is that we've lost 2-0 and now we have to take at least a point against Portugal - or even better, three," he said.
"I think that we registered how well the fans supported us. We saw that in Austria during qualifying too. We know that we can play differently, but we didn't bring that onto the field today unfortunately. We need to bounce back as quickly as possible and bring a level of calmness into our game.
"Head up, shake it off and we've got to give it all again. That's all that counts at a tournament. We need to get the players back on their feet and re-build their confidence."