Mauricio Pochettino has suggested that Tottenham Hotspur have paid a price for the late completion of their summer transfer business and has made it plain that the club will have to be quicker and smarter next time.

The manager will be restricted in the January window as his Champions League squad already contains the maximum of 17 foreign players – and that number does not include the fit-again Érik Lamela, whom he is keen to reintegrate for the knockout stage.

Pochettino said he would focus next month on trying to “take advantage of the English market and add an English player”, together with the drive to promote English youngsters from the academy. But he wants to use January, primarily, as a means to prepare the summer business; to steal a march on rivals, after he felt the club failed to do so last summer.

Pochettino signed Davinson Sánchez, Paulo Gazzaniga, Juan Foyth, Serge Aurier and Fernando Llorente in the final two weeks of August. Foyth, Aurier and Llorente came in the last 48 hours – the latest example of the chairman Daniel Levy’s penchant for taking deals down to the wire. Pochettino was quick to spell out the downside of that approach.

“This summer was a very good example because we signed good players but it was so late and with no pre-season [for them], you pay,” Pochettino said. “You then need six or seven months for the player to be fit, adapt himself in everything and that is always against us.

“The most important thing that we have been talking about is to identify our targets and, on 3 July, when we start our pre-season, they are here. If we don’t, it’s so difficult for them to help the team and then, during the season, you are going to pay. It’s so important today to identify your targets for the summer. If not and we wait until May and, before we sign, we sell, it’s so difficult to bring in players that can help.”

Pochettino betrayed an element of frustration at Tottenham’s summer business when he was asked whether he needed to qualify once more for the Champions League to attract the best players. “But you have the very good example of last season,” he said. “How did we finish? In second place. And we attract? We attract?”

The questioner tried to be positive and highlighted how Sánchez had been signed. “We attract a 21-year-old,” Pochettino said, pointedly. “Yes or no?”

Pochettino is painfully aware that the summer market will be particularly difficult because of the World Cup and the fact that the window will close for incoming signings on the Thursday before the Premier League season begins.

It has made him more determined to act swiftly – possibly tying up some business for the summer in January, in the same way that Dele Alli was signed from MK Dons in the winter window of 2015 with an agreement for a five-month loan-back. Pochettino would like to put something similar in place for Fulham’s Ryan Sessegnon.

“The Dele signing is a very good example of the need to anticipate,” Pochettino said. “We cannot be reactive because if we are, we are going to lose. If we are going to compete in the same period with City, United, Liverpool or Chelsea, then we are going to struggle to bring in the players we want. Maybe we need to sign the player in January and they can join in the summer.

“We tried to make early signings last summer but we could not, for different reasons. Now, we are going to try again to do things early. If we cannot again, I am going to say: ‘Come on, we could not again!’”

Pochettino said that Tottenham had recall clauses in the loans that have taken Josh Onomah and Cameron Carter-Vickers to Aston Villa and Sheffield United, respectively. “We have the possibility to bring them back,” he said.