Sunderland manager David Moyes was pleased with their deadline day swoop for Jason Denayer.
Manchester City defender Denayer has penned a season-long loan deal.
“We brought in Jason, who can play centre-half, he can play full-back - they speak incredibly highly of him at Celtic, where he spent time on loan and was named Scottish Young Player of the Year," Moyes told the Evening Chronicle.
“He went and played at Galatasaray last year, and he only came on the market late on Wednesday night.
“He was interesting to us, because I don't think having Lamine Kone, Papy Djilobodji, and John O'Shea was enough to get us through the season. With the possibility of injuries and suspensions, you really need four centre-backs.
“I also wanted him because he gives me the flexibility to play three at the back alongside Kone and Djilobodji, which I will do at times."