Delighted to sign on the line
It has been no secret that the Blues have been in the market for a central defender, due to the long-term injury to Kurt Zouma and John Terry almost definitely into his final season at Stamford Bridge.
The 25-year-old has signed a five-year contract with the club, with the brother of Xabi having experienced English football previously with Sunderland and Bolton Wanderers.
Former Blues defender, and current Paris Saint-Germain defender David Luiz, expecting to join him at the Bridge in the final hours of the window, the Spaniard shared his delight at signing for the club.
Alonso told chelseafc.com: "I’m very happy. It’s a step up in my career and I think this is the perfect place for me to continue developing." He firmly believes, "It’s time for me to win some titles."
He continued: "It was an easy decision for me to make when I heard the club were interested in signing me."
The Spaniard was adamant that, "My family and close friends know Chelsea is the club I have dreamed about playing for so I’m really excited about the challenge and I'm looking forward to working with my new team-mates."
Making the move back
The big deal on deadline day seems to be the return of Luiz from the French capital. The Brazilian became the world's most-expensive defender after his £50 million in 2014, and have the club have confirmed his return.
A Chelsea FC statement read: "Chelsea Football Club and Paris Saint-Germain have agreed terms for the transfer of David Luiz back to London."
It concluded, "The move is now subject to him agreeing personal terms and passing a medical."
Chelsea will take on Swansea City at the Liberty Stadium on Sunday, September 11 with kick-off at 4pm BST.