Chelsea are to pay a world record €80m (£72 million) fee for Athletic Bilbao Goalkeeper Kepa Arrizabalaga after agreeing to meet his buy-out clause.

The 23-year-old is due to fly to London on Wednesday in a move that will trigger the departure of Thibaut Courtois to Real Madrid. Though young and relatively raw, 6ft 3in Kepa is regarded as one of the best prospects to emerge from Spain and was named in his country’s World Cup squad.

The deal for Kepa is more than the €75m (£66.8m) paid by Liverpool for Alisson last month.

Remarkably, Kepa was all set to join Real Madrid in January for €20m, and had even passed a medical, but at the last moment Madrid manager Zinedine Zidane persuaded the board not to make the deal.

Kepa is expected to undergo a medical on Wednesday and could even make his debut in Saturday’s Premier League opener at Huddersfield.

“I saw him one year ago [when I was] at Naples, and my first impression was he was a very good goalkeeper,” said Maurizio Sarri after Chelsea’s goalless draw with Lyon on Tuesday last night.

“Very young, but very, very good.”

That Chelsea went for Kepa and not a cheaper option such as Jack Butland and Sergio Rico of Stoke and Sevilla respectively, is a surprise.

But after failing to address the Courtois situation all summer, and with time running out in the window, Chelsea made the plunge.

The deal frees up Chelsea to allow Thibaut Courtois, who failed to report for training for a second day in succession, to move to Real Madrid in the next couple of days.