Liverpool boss Jurgen Klopp has been among the most active in the summer transfer window, signing the likes of Fabinho, Alisson, Naby Keita and Xherdan Shaqiri.
Thompson is impressed with the way his former club acted in the window.
“It was within 48 hours of losing the Champions League final Fabinho was announced as our first signing, a holding midfielder to maybe put a bit of pressure on Jordan Henderson,” Thompson told Sky Sports News.
“Liverpool have their business done nice and early, unlike some clubs who have been caught out. For Liverpool, though, I think it has been a fantastic window.”
Thompson believes the signing of goalkeeper Alisson from Roma in a £67million deal in July, could prove the club’s most important signing.
“What we are really pleased about is the goalkeeping situation,” he said. “Jurgen was very, very protective of both his goalkeepers, certain-ly after the Champions League final.
“But we all thought this had to be nailed down and there has to be a change. And he did it and he spent very, very big. That was fantastic and it gives everyone a lift. And not just the fans, the team and the players too.
“So that is a massive area and if Liverpool go on and win the league title, he will be the signing of the window. We have seen how well Da-vid de Gea has done at Man Utd and the points that he saves. That was one are that needed to be sorted.
“This fella has kept Ederson out of the national side, so he is a good goalkeeper. But no matter how much you have paid – not just for a ‘keeper, but an outfield player – you just do not know what they are going to be like and how they will react in the Premier League, particu-larly when they come from abroad.
“That is why I am saying, if he copes, does the business and saves us points, it could be a fantastic position.”