New Tottenham Hotspur boss Jose Mourinho was quick to apologise to midfielder Eric Dier for yanking him off in the 29th minute of their 4-2 victory over Olympiacos in the Champions League.

Spurs found themselves 2-0 down early on thanks to Youssef El Arabi and Ruben Semedo but a brace from Harry Kane and goals from Dele Alli and Serge Aurier sealed their progress into the knock-out stages at the Tottenham Hotspur Stadium.

Although it did come at a price as boss Mourinho opted to bring on Christian Eriksen for Dier after going 2-0 down to bring more creativity into the midfield.

"Well the first thing, the most difficult moment for me, was not when Olympiacos the first or second goal, the most difficult moment for me was when I made the change in the first half.

"It hurt the player but it hurt myself. It's not easy for the player nor easy for myself.

"It's important that the player understood and I was lucky that my choice was a very intelligent boy who has a very good understanding of what the team is, because I did it for the team.

"It was not about his performance. It was about what the team needs.

"We are losing 2-0 and in a very difficult situation in that moment and I felt in that moment that one positional midfielder was more than enough.

"I thought I needed a second creative player who could play with Alli in that triangle, an open triangle as I used to call it, not a closed triangle like we were with Dier and Harry Winks.

"So I had to do it for the team and I apologise to Eric despite him knowing that I did it for the team and not with any intention to hurt him."

The former Chelsea manager also praised the ballboy for his quick distribution that led to Spurs second goal in the match.

"To do that you have to be a very good ball. I was, between 10 and 15, 16-years-old, a very good ball boy. He is a very good ball, understands the game, reads the game.

"He's not there just to look to the stands, the lights or the scarves. He's there reading the game and playing the game very well.

"In the end I wanted him to come back to celebrate in the dressing room with the players but he had gone, I don't know where he is. But a very good ball boy, very good."