Portugal coach Fernando Santos felt his side conceded "abnormal" goals as they let a two-goal lead slip against Tunisia.
The Euro 2016 champions, who were without Cristiano Ronaldo, led in Braga thanks to goals from Andre Silva and Joao Mario only to collapse.
Anice Badri and Fakhreddine Ben Youssef both took advantage of slack defending to earn a 2-2 draw for Tunisia, leaving Santos frustrated.
"The result was not certain, I wanted to win," Santos told reporters. "A draw is not a good result and never will be.
"We came to win the game, we played the game very well - a fast, well-circulated team with total domination of the game.
"At 2-0 we started to make more mistakes collectively. For the second goal we let the opponent score. We had to approach the first goal in a different way.
"The team is conceding goals in an abnormal way, we have to think about that."
FIN DU MATCH : Match nul (2-2) entre le Portugal et la Tunisie. Les Tunisiens sont revenus au score après avoir été menés 2-0 grâce à des buts de Badri (37') et Ben Youssef (63') ! May 28, 2018
Portugal looked set to clinch victory with the score at 2-1 in the second half when William Carvalho headed in a free-kick from Ricardo Quaresma, but the goal was ruled out for offside.
"We started to allow the Tunisians to go out and play," Santos said.
"We had a fantastic opportunity, we did not make it 3-1 and we ended up suffering the second goal. It's not normal, I'm not very happy about it.
"I have a fantastic team, the attitude has to do with our position in the field, if we aim to win every game we play, we have to score goals."
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