Arsenal have confirmed the signing of left-back Nacho Monreal from Malaga for an undisclosed fee.
The Gunners looked to bolster their defence after Kieran Gibbs suffered a thigh injury during Wednesday's 2-2 draw with Liverpool.
On transfer deadline day, it emerged that they had targeted Spain international Monreal, with reports suggesting he had flown to London to discuss personal terms and undergo a medical.
Although the fee is undisclosed, it is believed to be in the region of £8.5 million, and Arsenal have confirmed that the player has signed a long-term contract.
Arsenal boss Arsene Wenger told the club's official website: "We are delighted that Nacho Monreal has agreed to join us. We have been monitoring him for some time now and are really pleased that we’ve been able to agree this move today.
"Monreal is a strong left-sided defender with good experience at both club and international level. He is a technically gifted player, a good crosser in the final third and strong in the air.
"Monreal will add quality to our squad and, of course, to our defensive unit. We all look forward to him playing for us."