Spurs, who played in the Europa Conference League last season, created the better chances before Sporting substitutes Paulinho and Arthur Gomes scored in added time to inflict a first defeat of the season on the London club.

"The level of the Champions League is high. It's very high. You know that to play in this competition you have to reduce the mistakes, because at the end you can pay," Conte told reporters.

"Tonight we paid a lot and now we are talking about a loss against a team that showed (they are) used to playing in this competition...You have to continue to improve yourself but this is normal.

"Don't forget that last season in November we lost to Mura in the Conference League in Slovenia. I think that we then made an important step forward, because tonight in my opinion it was more fair a draw than a defeat honestly."

Spurs host Leicester City in the Premier League on Saturday.