LONDON, Aug. 30 (Xinhua) -- Chelsea has completed the signing of Argentina winger Alejandro Garnacho from Manchester United in a deal worth 40 million pounds.

The 21-year-old has penned a long-term contract at Stamford Bridge, committing his future to the club until 2032.

"It's an incredible moment for my family and I to join this great club," Garnacho told Chelsea's club website. "I can't wait to get started. I watched the Club World Cup and to join the world champions is special - we're the best team in the world!"

Garnacho becomes Chelsea's ninth signing of the summer and the fifth attacking recruit, following the arrivals of Joao Pedro, Liam Delap, Estevao, and Jamie Gittens.  ■