Arsenal have completed the signing of Germany international defender Shkodran Mustafi, who has agreed a long-term contract after joining from Valencia for an undisclosed fee.
The 24-year-old's transfer was confirmed on Tuesday, after manager Arsene Wenger announced following Saturday's 3-1 Premier League win over Watford that the completion of paperwork was the final hurdle to clear.
Wenger had been under pressure for a perceived lack of activity in the window, with Mustafi arriving to bolster a defence that has lost Per Mertesacker and Gabriel Paulista to injury.
The Frenchman said in an official club statement: "He is at the right age. He has good experience. He is a very focused player who can play with the ball as well.
"We have taken a great player but have prepared well for the future."