Liverpool reluctantly agreed to sell Coutinho to Barcelona for £142 million this week after the Brazil international made it clear to everyone at Anfield that he wanted to move to the Camp Nou.

Barca and Madrid have a history of forcing even the biggest European clubs to sell their best players and Cristiano Ronaldo, Luis Suarez and Spurs pair Luka Modric and Gareth Bale have all moved from England to Spain in the past decade.

Kane -- who scored twice in Spurs' 3-0 win over AFC Wimbledon in the FA Cup third-round -- has been repeatedly linked with a move to Madrid this season, although Spurs have not held talks with anyone.

"I think it is a massive example or massive point to show how this business is, how difficult it is for the clubs to keep their best players," Pochettino said of the Coutinho transfer.

"Liverpool is one of the best clubs in the world and look when Coutinho wants to leave how difficult it is to keep your best player. Liverpool wanted to keep [him] but it was difficult to keep him -- and look what happened with Cristiano Ronaldo and Man United and [Zinedine] Zidane at Juventus, [Luis] Figo in Barcelona.

"It is a lot of examples that it is so, so tough to keep your best player if the player says he wants to leave.

"That is why it is so important how you care for your players -- it is why you need to anticipate things. It is so important to work with the human side and then to provide the player the club and the team an exciting moment and try and build a project that they feel comfortable with and they are happy to be with you.

"Look, that is a good point to assess and talk. Today when a player decides to leave, look what happens. If another club pays the type of money they pay -- like Barcelona with Liverpool -- how do you stop it? I hear what clubs say. It is so difficult, our job."

Kane has previously said he would like to spend his entire career at Tottenham and, not for the first time, Pochettino compared him to Roma legend Francesco Totti, who spent a quarter of a century at the Serie A club.

Despite suggesting that Kane could be a special case, Pochettino admitted that Spurs cannot force anyone to stay at the club long-term if they want to leave.

"Harry is so special, because he loves Tottenham and he has always been at Tottenham, but we need to be clever how we manage him," Pochettino said. "The player needs to choose to stay here -- you cannot force the player to stay here.

"Our chose is to try to work together and try to achieve everything we want at the club and of course Harry is such a special player. I told him only a few special players can spent all their career in one club.

"I think Harry is this type of a player who can stay all his career at Tottenham because he loves Tottenham. But in football you cannot be sure. It is today, the present; tomorrow, after tomorrow, you need to doubt. That is why it is so important to work together and try to achieve all that you want.

"And of course this present at Tottenham, this future at Tottenham, this project is so exciting and I hope, we hope, that all together we spent a lot of time here and try to win trophies and achieve what we want."

Kane scored twice in two minutes just after the hour and Jan Vertonghen added a third -- his first Tottenham goal since October 2013 -- in Sunday's comfortable win at Wembley.

"I think it was a solid performance," Pochettino added. "I think we created a lot of chances. In the first half we played well, created chances but again it was difficult to score. I think in the second half we created chances and deserved to score and go through to the next round."