Mauricio Pochettino admits Tottenham were too quick to sell Gylfi Sigurdsson as the Swansea midfielder would be "perfect" for his current team.
Sigurdsson will be hoping to deliver Pochettino a timely reminder of his creative talents when the Swans face Spurs on Saturday at White Hart Lane.
He was one of the first players to depart after the Argentinian took charge in the summer of 2014, rejoining Swansea in a deal that saw Ben Davies and Michel Vorm move in the other direction.
The 27-year-old had struggled for a regular starting place during two stop-start seasons in north London but he quickly rediscovered his rhythm at Swansea, with seven goals and 10 assists in 2014-15 and then 11 goals and four assists last term.
Sigurdsson has four goals and four assists already in the current campaign - the kind of attacking output Tottenham have been so lacking in recent weeks.
"I think after he moved to Swansea and we saw his development at Swansea he was a perfect player for us," Pochettino said.
"But in that moment it was the club decision and his decision to move to Swansea and find another way.
"Every time we meet him and see him he shows his quality not only as a player but like a man. All the people here talk very highly about him.
"It's a shame but sometimes in football you never know what will happen in the future."
Pochettino's priority upon taking the Tottenham job two and a half years ago was to clear out a bloated squad that had proven so disappointing under both Andre Villas-Boas and Tim Sherwood.
He allowed nine senior players to leave in his first year, and another 10 in his second, with Sigurdsson shown the door during a pre-season tour in the United States.
"When we arrive at Tottenham he was a player that was difficult to assess," Pochettino said.
"The decision was when we were in Seattle to play the first friendly game. I remember he was in the starting 11 to play that match and I had a call to say, 'Okay, the agreement is done with Swansea'.
"It is difficult to assess him. In that moment we had 34 senior players and to take the decision was too difficult to assess because we did not have time enough."
Source: PA
