Guler marked his European championship debut with a sublime strike in Turkey's opening 3-1 win over Georgia but the Guler was only introduced for the final 20 minutes against the Portuguese.

Guler made only 10 league appearances for his club side Real Madrid last season and would have been at risk of injury had he played from the start on Saturday, Montella said, adding that a lack of competitive first-team action was a problem for his squad.

"Arda wasn't fit to play I can say clearly he could not play more than 30 minutes without increasing the risk. So there was also a temptation of not putting him in 20 minutes from the end, but finally I gave in because good players must play my opinion," Montella told reporters.

"Because we often tend to forget about it that most of our footballers are not used to playing with continuity in their clubs and I am talking about one game a week... when you play once every four days, it's another sport you need to be physically fit, you need to be prepared.

"Arda is a great, smart guy he is very passionate about his country, is proud of his country. But even though he knew that he was risking an injury by playing, he wanted to be on the pitch."

The result left Turkey second in the group with three points, knowing a draw or better in their final game against Czech Republic on Wednesday would see them safely into the last 16.

Turkey fell behind to a clinical Bernardo Silva goal after 21 minutes before conceding a farcical own goal seven minutes later. Samet Akaydin failed to spot his keeper Altay Bayindir advancing to collect the ball and knocked it past him into the goal.

Bruno Fernandes wrapped up the scoring with a tap-in after being unselfishly teed up by Cristiano Ronaldo in the second half.

Montella, however, felt the game was fairly even although Portugal were able to ruthlessly punish Turkey's errors.

"We started well the first 20 minutes or so and we had our own opportunities, but we couldn't make the most of them. We were punished at the first mistake," he said.

"But it was a balanced game until the goal. The second goal we were very unlucky, these things happen in football and it shifted the balance but I think that over the game, we've played equally with one of the best teams in Europe.

"Sometimes we lacked a bit of boldness probably because we were feeling too much this game."