Mauricio Pochettino has said Tottenham Hotspur are in a "very tough period" because of their new stadium project – just as Arsenal were when they built the Emirates Stadium – as he sought to explain why the club did not sign the back-up striker that some supporters had wanted in January.

The manager knew the question about the lack of specialised cover for Harry Kane would come on Thursday and he had clearly given plenty of thought to his answer. During a five-minute monologue, which was without precedent from his time in English football, Pochettino went into great detail about the factors that had shaped the club's recent approach to the transfer market.

They included the balance and harmony of the squad, which has helped to power the club to a surprise Premier League title challenge – and the imperative not to upset that – together with the importance of staying away from signings who were not a significant upgrade on what they already had, and might block the progress of young talent from the academy.

Pochettino talked more generally about the project he had signed up to in the summer of 2014 when he joined from Southampton and his words echoed those of the Spurs chairman, Daniel Levy, after the closure of last summer's transfer window.

Back then, on 2 September, Levy had said that a policy of “pragmatic player trading has been important in the way we have run the business of the club and in getting us to the position where we have now been able to start work on a new stadium – the one thing that has the ability to take this club to the next level of competitiveness.”

Tottenham intend to move into the new stadium, which will be built adjacent to the existing White Hart Lane site, in time for the 2018-19 season. The estimated cost is £400m-£450m.

Pochettino said: “I have read a lot about Arsène Wenger saying the toughest period for Arsenal was in the period that they built their stadium and I think you need to know, and the people need to know, that this is a very tough period for us. We need to be careful because we need to arrive at the new stadium in very good condition to try to fight for everything, and try to show that we are one of the best clubs and teams in the world.”

Pragmatism has, indeed, been the watchword in the transfer market under Pochettino. He is £6.3m in credit over his four windows on permanent fees spent and he has tried to be smart and extremely specific in his dealings.

He would like to have signed an out-and-out striker last summer or in January but the deals for players that he wanted, such as Saido Berahino of West Bromwich Albion and Fulham’s Moussa Dembélé, could not be concluded.

Given that, Pochettino has preferred to work with the players he has, rather than spend for the sake of it, and save the money – which is available – for a signing that could truly make the difference.

“Our people need to understand that Tottenham changed their vision, not in terms of the football but in the way that we take decisions,” Pochettino said. “For us, it is very important to keep the balance and find the right player, not only the strikers but in different positions.

“You need to realise that to improve our squad today is a very difficult job. It’s easier to find different names on the market, to pay the money and to bring players but it’s not the way that we decided upon 18 months ago. It’s easier for me to say: ‘OK, we bring this and this, and this player but if we don’t believe that can improve our squad, why do it?”

Pochettino has long insisted that Son Heung-min and Nacer Chadli can provide cover up front for Kane while he namechecked two academy strikers – the 18-year-old Shayon Harrison and the 17-year-old Kaz Sterling – as players for whom he wanted to clear a pathway to the first team. As an aside, Tottenham sold Shaq Coulthirst, who had been their striker at under-21 level over the first half of the season, to Peterborough United on 22 January.

“We have many players that can play like a striker, like Sonny or Chadli, who have shown they can score,” Pochettino said. “And we have younger players that train with us like Shayon and, in behind him, Sterling and different players. We have to believe in the younger players because for our future they will be very important players.”

Pochettino highlighted Tottenham’s current position of strength with a nod towards their goal difference of plus-25 – the best in the league – and described his squad as having the “perfect balance”.

“If, at the end of the season, we achieve big things, OK, everyone is happy,” Pochettino continued. “But if not, I think we have created a very good basis to achieve next season. The project is very clear and we need to believe more when we have a difficult moment to take decisions.

“Our key is to be all together and to feel that. This is an important thing and a message for all of our supporters. The energy that we create and the synergy between our supporters and the team is very important for our future.”

(Guardian service)