Wonderkid Yisa Alao becomes Liam Rosenior's first signing at Chelsea

The transfer, officially announced on Monday afternoon, is understood to be worth just over 500,000 pounds initially, with performance-related add-ons that could see the total fee rise to roughly double that figure.

Chelsea ultimately beat off interest from both Manchester United and Liverpool to land the teenage defender.

United had previously submitted a 450,000-pound bid for Alao before Christmas, which was rejected by Sheffield Wednesday, and also held talks in an attempt to revive their pursuit.

Alao has been one of Sheffield Wednesday's breakthrough players this season, with his displays attracting significant attention from top-flight scouts.

A product of the club's academy, he made his senior debut at just 16 years old in a Carabao Cup tie against Bolton in August. He has gone on to make five first-team appearances during the current campaign and featured for 60 minutes in Wednesday's FA Cup defeat to Brentford earlier this month.

Born in Doncaster, Alao is viewed as a long-term prospect by Chelsea, who continue to operate a youth-focused transfer strategy.

The left-back will initially link up with the club's academy setup rather than joining the first-team environment, and he will not immediately be part of Liam Rosenior's senior squad.

Alao has signed a contract at Stamford Bridge running until 2028, underlining Chelsea's commitment to his development and future potential.

"Chelsea is pleased to announce the signing of Yisa Alao, with the left-back agreeing a contract with the Blues until 2028," the club stated.

"The 17-year-old came through Sheffield Wednesday's academy and made his senior debut for the Owls in August.

"Alao has since played four more games, starting Wednesday's recent FA Cup tie against Brentford and Championship match against Portsmouth. Welcome to Chelsea, Yisa!"