For many Tottenham Hotspur players, this was the worst summer of their careers. In late April and May their Premier League title dreams collapsed, with painful draws against West Bromwich Albion and Chelsea before embarrassing defeats to Southampton and Newcastle United. They fell so far they finished the season in third.

Then, in June and July, most of Spurs’ team were crushed or frustrated in their international efforts. Eight Spurs players suffered as England and Belgium embarrassingly crashed out of Euro 2016. Hugo Lloris captained France to their Paris final, which they lost. Erik Lamela’s Argentina were runners up in the Copa America for the second year in a row.

The players needed to be lifted when they returned in late July but what they got from Mauricio Pochettino was a brutal assessment of where last season had gone wrong, especially the 5-1 defeat at St James’ Park. Pochettino was furious with that performance, and with the fact that, as it was the last game of the season, he did not get the chance to tell his players how he felt at the time.

Pochettino took a young Spurs squad to Australia in late July but when he returned to Enfield he met up with his senior players who he had not seen for two months. And he told them how personally offended he had been by that Newcastle collapse.

“When we got back from Australia, we talked a bit about it,” Pochettino revealed on Thursday afternoon. “The players needed to hear my feelings, how I felt after the game and after the season, because there was no time to share [then]. I explained my point of view and my feelings.”

Those feelings were furious. “I just told them, that if I had had the opportunity to kill them, then I would have done. I wanted to kill all of them. And kill myself too. I am very honest with them and they are very honest with me. That is a very good relationship.”

The words might sound harsh but that is the medicine Pochettino has decided upon for his players. This is his third season in charge at Tottenham and only Mark Hughes and Arsene Wenger have managed their clubs continuously in the Premier League for longer. Pochettino has spent all summer agonising over last season, at the cost of any enjoyment of his holidays. And he decided that it was a lack of mental maturity over the final stretch that cost them the title.

Tottenham Hotspur summer transfer targets Show all 8 1 /8 Tottenham Hotspur summer transfer targets Tottenham Hotspur summer transfer targets Georges-Kevin N’Koudou (Marseilles) French winger, a pacy, talented dribbler who is comfortable on either foot. Has been closing in on a move to White Hart Lane all week, with the 21-year-old’s switch seemingly held up by ongoing complications with Clinton Njie moving the other way. Only spent one year at the Stade Velodrome but was included in Uefa’s Best player in Europe poll for last season and caught the eye of the London side when they were scouting former target Michy Batshuayi, who has since joined Chelsea. Getty Tottenham Hotspur summer transfer targets Mauro Icardi (Internazionale) Argentine forward has spent three prolific years at Internazionale and could further ease the striking burden on Harry Kane, following the recent arrival at Spurs of Vincent Janssen. The Serie A top scorer of two seasons ago would link up with fellow Argentines Mauricio Pochettino, Federico Fazio and Erik Lamela in north London, although he would not come cheap and Arsenal are also vying for his signature. Getty Tottenham Hotspur summer transfer targets Ragnar Sigurdsson (Krasnodar) Icelandic centre-back shot to prominence when scoring against England at Euro 2016 last month. Also chased by Leicester and Liverpool – whom the centre-back supports-, the 30-year-old would only ever be back-up to the preferred trio of Jan Vertonghen, Toby Alderweireld and Kevin Wimmer but could offer a relatively cheap back-up for Spurs’ Cup matches. Has spoken of his wish to leave Russia after impressing at the Euros. Getty Tottenham Hotspur summer transfer targets Moussa Sissoko (Newcastle) French powerhouse has made no secret of his desire to leave the relegated Magpies, with Arsenal and Liverpool among the other clubs linked with a move. Can appear unbeatable on his day, as was the case against Tottenham on the final day of last season and in patches of the Euro 2016 final, but those days are few and far between most of the time. Could command a fee in excess of £30m, with Borussia Dortmund, Juventus and Real Madrid also mentioned. Getty Tottenham Hotspur summer transfer targets Jonas Hector (Cologne) German left-back impressed at the Euros as his side made the semi-finals, with Barcelona and, surprise surprise, Liverpool also linked. The Catalan side’s purchasing of Lucas Digne earlier this month could enhance the chances of Hector moving to the Premier League, with £15m likely to be enough. Equally at home in defensive midfield, his size also poses a threat at set-pieces and on counter-attacks, a style suited to Mauricio Pochettino’s Spurs. Getty Tottenham Hotspur summer transfer targets Cristian Tello (Barcelona) Spanish forward has failed to settle at the Nou Camp and has spent loan spells at Porto and Fiorentina. Worked with Spurs coach Mauricio Pochettino at previous club Espanyol and could link up with the Argentine again to bolster the London club’s attacking options. Pacy and also an option on the wings, Tello would provide a foil for the more central Vincent Janssen and Harry Kane. His agent was reported to have flown to London for talks with Spurs last week. Getty Tottenham Hotspur summer transfer targets Matthias Ginter (Borussia Dortmund) With some many new arrivals at the Westfalenstadion this summer, some players will have to leave to make room for them, and the centre-back has reportedly been the subject of a £12m bid from Spurs, with Arsenal and West Ham observing developments. Unlikely to go straight into the Spurs starting line-up, but would provide experienced back-up as the London side prepare for their return to Champions League exertions. Getty Tottenham Hotspur summer transfer targets Roberto Pereyra (Juventus) Argentine playmaker, 25, who is also being watched by Watford and West Ham. Hard running and can play on the wing, in the middle or up front. Began his career at River Plate. A £15m bid for the playmaker could seal the deal for Spurs, who has struggled to establish himself in Turin but would offer competition for places. Tottenham’s forthcoming Champions League campaign is said to have turned his head, above a move to the Hammers. Getty

“After a very tough season, it was tough to manage the last few weeks,” Pochettino explained. “After Chelsea it was difficult to manage the situation, because it was impossible to win the title. Then in your mind you are tired, after the whole season, it was a big stress. We lacked focus to finish the season in the way that we deserved. Football is about experience and learning to improve. Our team today is more mature than last season.”

Maturity, more than anything else, is what Pochettino demands from his players this year. This squad has developed under him better than anyone could have expected. Now they need to take the final step, and for Pochettino that means getting back into their heads.

“Football is tactical, is physical, technical, but it is mental, more mental than [it was] many years ago,” Pochettino said. “Today, to be strong in your mind is important. We need to know how to improve our mental state. That is very, very important. I think this was key in the last few games in last season.”

Mauricio Pochettino was left angry by Spurs' collapse last season (Getty)

On the training ground there is very little else for Spurs to work on. In the transfer market they have only signed two squad players, Victor Wanyama and Vincent Janssen. “To move on the team, to improve, to achieve another level, it is here that we need to improve. It is not tactical, it is not philosophical, because after two years we know very well how we need to play. It is here in our heads that we need to improve.”

That is why Pochettino started by tearing into his senior players, and getting some closure on the disaster of folding against a relegated 10-man team and losing as badly as they did. But since then he has been delighted by the intensity his players have shown in training, as they look hungry to improve on last season. Their international disappointments do not weigh heavy upon them.

“No impact,” Pochettino said of any Euro-hangover. “It’s strange, but no impact. The good thing is that they are very happy to be back here training together on the training ground. That was our worry as a coaching staff, how they would assimilate the situation. But it is unbelievable how they behave and the energy they show now. They completely forget the Euros, and they are very focused and excited on the season we have ahead.”

This is a grown-up group now and their leader Hugo Lloris was closer than anyone to a trophy, as his France team lost their final, just over one month ago. But all of that is forgotten now, as Spurs prepare to go to Goodison Park on Saturday afternoon.