Mauricio Pochettino says Gylfi Sigurdsson would have been a “perfect player” for him at Tottenham Hotspur, as he lamented how the midfielder was allowed to leave for Swansea City in the summer of 2014.

Pochettino had been appointed as the Spurs manager on 27 May of that year and he named Sigurdsson in the starting XI for his first match in charge on 19 July – a friendly against Seattle Sounders on the pre-season tour of the United States. But, 40 minutes before kick-off, Pochettino was forced to withdraw Sigurdsson from the lineup, after taking a call from the board to tell him a deal had been agreed with Swansea. It was essentially a swap in which the defender Ben Davies joined from the Liberty Stadium.

Sigurdsson, who returns to White Hart Lane on Saturday with Swansea, was brought to Tottenham by André Villas-Boas in the summer of 2012 and was used more often as a substitute than a starter in the Premier League. He scored 13 goals in all competitions during his two seasons at Tottenham.

He has blossomed at Swansea – where he had an eye-catching loan spell from Hoffenheim in the second half of 2011-12. The 27-year-old scored nine goals in his first campaign at the club and 11 last season. He has five this season.

Pochettino wants greater productivity from his attacking midfielders and it is not difficult to see why he might look longingly at Sigurdsson, who has also tended to play well against Tottenham.

“I think after he moved to Swansea and we saw his development at Swansea, he was a perfect player for us,” Pochettino said. “But it was a 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. There are no regrets.

“When we arrived at Tottenham we had 34 senior players and it was difficult to assess them all in the first few weeks, because we did not have enough time. The decision when we were in Seattle was for him to play the first friendly game. I remember he was in the starting XI to play that match and I had a call to say: ‘OK, the agreement is done with Swansea.’ When the club and player decide to move, there is nothing you can do about that.”

Pochettino turned the focus inwards at Tottenham this week – the club’s first without a midweek fixture since August, excluding international breaks. The team has endured a bruising run, winning once in 10 matches and exiting the Champions League and the EFL Cup.

There have been double training sessions, in which there has been intense focus on the fine details, and many individual and collective meetings. Pochettino felt that even in defeat at Chelsea last Saturday, his players had recovered the feeling from their victory over Manchester City on 2 October – in that they performed well. But what he really needs against Swansea is a win.

“We needed a week like this, a clear week to refresh the concept and to realise where we are going,” Pochettino said. “We’ve talked about mentality. It’s not about technical ability, it’s about being more fresh to compete. That is the gap we need to reduce with the teams that have the ability to compete every three days.”