Jose Mourinho admitted he's concerned about life without Harry Kane - as Spurs failed to finish off Boro.
With Kane ruled out until March with a hamstring injury, Spurs battled for a draw at the Riverside Stadium and lacked a killer punch.
And Mourinho reckons it will take time for his side to get used to playing “without a No9, or a striker.”
He said: “The boys did what they can, you cannot transform Lucas or Son into a number 9 like Harry Kane.
“Until Harry is back, obviously every minute he doesn't play means a lot to us, it is a big loss for us, but we have to accept it and we have to fight with the boys that are available.
“We have to try other things and that is what we are going to do. So in this moment it is not going to be 'Harry, Harry, Harry, Harry'. We have what we have and we stick with them.
“It's a new thing for the team to play without Harry, without a striker.
"We tried to give them the mobility of Son and Lucas, we tried to give that to the team but it was not easy.
“If football was about how many times you arrive in scoring positions we would win by a huge score.
"Football's not about arriving there, it's about the right assists, the right pass, the spin of the ball and direction of the cross. We missed so many.
"Sometimes the way players are frustrated on the pitch, I'm frustrated on the sidelines. That's the way it is.
"In the end, everyone that was in the stadium had a real cup match when you're confused a little bit about the divisions.
“We played six attacking players so we took our risks. The boys accepted it and the boys tried.
"They deserved to win by their dominance but I think it's fair to say that Middlesbrough deserve their right to go to London and play us and try to stay in the competition."
