Mauricio Pochettino says basic defensive errors are to blame for Tottenham’s slow start to the season – not their tardiness in finishing their transfer business.

Spurs have only had one senior striker, Harry Kane, in the squad for their opening three Premier League games – and they continue to be frustrated in their attempts to sign West Bromwich Albion forward Saido Berahino as they prepare to host Everton tomorrow.

Clinton Njie arrived from Lyon two weeks ago but is yet to appear as he is short of fitness, while Bayer Leverkusen’s Son Heung-Min has come in four days before the end of the transfer window.

It is a familiar story at Spurs, with business being done late when the competitive action is already well under way – and Pochettino’s side have collected just two points from their opening three games.

However, the head coach believes that is due to mistakes on the field rather than in the boardroom, pointing to the goals that have been conceded.

An own goal condemned the Lilywhites to a 1-0 defeat at Manchester United on the opening day and they then threw away a 2-0 lead at home against Stoke in the final 12 minutes before conceding an equaliser against Leicester just 90 seconds after taking the lead last Saturday.

“If we have two points after three games it is not because we have a lack of players or because we don’t sign one striker or one keeper - it is because we make some mistakes like at Leicester, or Stoke after we were 2-0 up,” said Pochettino.

“This is not about signing a player, or non-football [issues], this is about competing much better and this is our focus now - to compete.

“Football is about playing, training, developing our philosophy, our tactics, the system and how you want to play. In football you need to be stronger, more focused and never switch off.

“The players will agree with me that this is good because we realise that we lost two points at Leicester. Come on, we scored and then we switched off. Never in football can you switch off for one second. After it happened it was mistake, mistake, mistake and we conceded a goal - and in the Premier League and in a professional team like this we need to avoid that.

“The opponent can score, we can concede a chance but [it should only be] because they deserve it, not because you give them to facility to do it, like against Stoke City, Manchester United or Leicester.”

Speaking on Thursday, before the signing of Son, Pochettino added: “I am optimistic for the future because if we add some real quality players I think our balance is better and only if we fix that I think it will be a great season.”

Some would suggest that a lack of experience is contributing to Tottenham’s issues. The average age of the starting line-up at Leicester was just under 25, while the substitutes were Tom Carroll, 23, Nabil Bentaleb, 20, and Dele Alli, 19.

With the exception of Toby Alderweireld, all of this summer’s recruits have also been under the age of 25. Kevin Wimmer and Njie are both 22 – as is striker target Berahino - while Son is 23.

“Everyone can give an opinion about this - the club needs experience or younger players. This is opinion, only opinion, and everyone has reasons,” said Pochettino. “The balance is right. We need some more players, and if we add the players we want I think the balance is perfect.”

Folloe me on Twitter @BenPearceSpurs