A great goalkeeper is no guarantee of winning major trophies, but not having one is a guarantee you will fall short when it matters.

Liverpool realised that to great cost on and off the pitch in the Champions League final last May. It was a major statement when they paid Roma £65 million – a world record at the time – for Alisson Becker. No one is querying that fee now.

“I would have paid double if I had known how good he is,” Jurgen Klopp told me immediately after Liverpool's win over Napoli on Tuesday night.

He is reaping the rewards of signing a goalkeeper with the potential to become the world’s best. When was the last time an Anfield keeper was staking such a claim?

For the last three years this title has been David de Gea’s. The performance he gave away at Arsenal last season was the best I have ever seen from a goalkeeper.

Without De Gea, Manchester United’s decline since the retirement of Sir Alex Ferguson would be steeper, yet he arrives at Anfield on Sunday with his position as the Premier League number one under threat, not just because of Alisson’s recent form, but the Spanish goalkeeper’s dip.