Tottenham boss Mauricio Pochettino says it was a "big mistake" for the Premier League to allow the transfer window to shut earlier than the rest of Europe.
Premier League clubs previously voted to close the transfer window before the season starts, but many European teams are still allowed to sign players.
Pochettino says it can "create a mess" for clubs in England.
"I think the Premier League cannot give this advantage to the European clubs," said the Argentine.
"That is another point to talk about, to argue that we are at a disadvantage to European clubs because they have 20 days more to operate.
"I think that was a big mistake for the Premier League to allow that - we open the door to different clubs in Europe to try to create confusion within your squad.
"I think after two seasons operating in this way, the Premier League realise that if Europe doesn't change, we need to go back and start to operate in the same way they operate now."
Pochettino says he understands closing the window before the season begins, but that it puts English clubs competing against their European counterparts in the Champions League at a disadvantage.
Spain's La Liga, Italy's Serie A, Germany's Bundesliga and France's Ligue 1 all have deadlines on 2 September.
"I think it's a big advantage for them. It can create a mess in clubs like us, clubs in England," added Pochettino.
However, the 47-year-old says he is a "happy man" with Tottenham's summer business.
The Premier League club signed Fulham winger Ryan Sessegnon and Argentina midfielder Giovani Lo Celso from Real Betis, having earlier broken their transfer record on Lyon midfielder Tanguy Ndombele.
"I'm more than happy with my squad after we close the window in England," added Pochettino.
Meanwhile, Brazilian forward Lucas Moura - who scored a hat-trick in Spurs' 3-2 Champions League semi-final second-leg victory at Ajax - has signed a one-year contract extension with the club until 2024.
The 26-year-old joined Tottenham from Paris St-Germain in January 2018 and scored 15 goals in 50 appearances last season.
Pochettino, starting his sixth season at Spurs, says he needs to win a trophy for this season to be "successful".
His side were beaten in the Champions League final by Liverpool in June and lost the 2015 League Cup final to Chelsea. Their best league finish under the Argentine is second in 2016-17.
"If you ask me personally, this season is not about finishing in the top four to be successful - although of course maybe that matters for the club," he said.
"But for me, it is about winning some title - the Carabao Cup, the FA Cup, the Premier League or the Champions League.
"If not, after last season's final, to be again in the top four and reach the semi-final of the Carabao Cup, it is like, 'Come on!'
"You are always there but you cannot touch the glory. That is personally - me. My personal target, objective, aim to be successful this season is to lift a trophy."