Chelsea goalkeeper Kepa Arrizabalaga stunned a capacity crowd at London's Wembley Stadium and left his manager fuming Sunday when he refused to be subbed off in the late stages of extra time in the English League Cup final against Manchester City.

With the two sides locked in a goalless draw, Kepa received treatment on his hamstring and Chelsea manager Maurizio Sarri summoned backup Willy Caballero to take his place for the forthcoming penalty shootout. There was just one problem: Kepa, the world’s most expensive goalkeeper after joining Chelsea in August for 80 million euros (then $93 million) from Spanish club Athletic Bilbao, would not withdraw.

Kepa waved to the bench and signaled that he was fine to continue. As Caballero strapped on his gloves and loosened up, Kepa remonstrated with Sarri and his assistants -- including Chelsea legend Gianfranco Zola. After a moment, referee Jon Moss consulted Kepa and Sarri before signaling that the substitution would not take place.

PUTIN ASKS FIFA FOR SUPPORT ON WORLD CUP LEGACY

As the fans jeered, a visibly enraged Sarri started down the tunnel as the final minutes of extra time ticked down before apparently recovering his composure and returning to the bench.

In the subsequent shootout, Kepa saved just one of Manchester City's five penalties, condemning Chelsea to a 4-3 defeat in the shootout that was overshadowed by the extraordinary disagreement between player and manager.

In his post-match news conference, Sarri described the issue as a "misunderstanding."

CASH-STRAPPED ITALIAN SOCCER CLUB FIELDS 7 PLAYERS IN BRUTAL LOSS

"I understood the goalkeeper had cramp and would be unable to go to the penalties," the Italian manager said. " ... I asked for a change for this physical problem and he said he hadn’t a physical problem. So he was right I think. I have to talk with [Kepa] but only to clarify because now I have understood very well the situation."

Chelsea's manager Maurizio Sarri, right, remonstrates with Kepa while substitute keeper Willy Caballero, obscured, waits to be subbed on. (AP Photo/Alastair Grant)

Chelsea's manager Maurizio Sarri, right, remonstrates with Kepa while substitute keeper Willy Caballero, obscured, waits to be subbed on. (AP Photo/Alastair Grant)

"I’ve never seen it (before),” Manchester City captain Vincent Kompany said when asked about the incident. “I wish I could do it every now and then when I don’t want to get subbed off.”

Former Chelsea manager Jose Mourinho, covering the match in Spain for the internet streaming service DAZN, said the situation made him “really sad.”

CLICK HERE TO GET THE FOX NEWS APP

“I don’t like that he leaves his coach and the assistant coach in a situation of great fragility,” Mourinho said, “and his teammate, who was ready to enter the match, and who in the end saw himself in the middle of a problematic situation that had nothing to do with him."

Chelsea, one of the richest clubs in English soccer, is currently sixth in the Premier League, 16 points behind leaders Liverpool. Sunday's defeat came six days after they were knocked out of the FA Cup by rivals Manchester United, leaving the UEFA Europa League as the club's best chance of winning a trophy this season.

The Associated Press contributed to this report.