Arsenal have finished the signing of Shkodran Mustafi from Valencia in an arrangement worth up to £35million.
The 24-year-old German center back turns into the Gunners' second signing of the day taking after the landing of Lucas Perez from Deportivo La Coruna for £17m.
The club's fresh debuts take Arsenal's spending near the £100m mark this late spring as they hope to rival the Manchester clubs and Chelsea at the highest point of the Premier League.
Middlesbrough have affirmed the marking of Calum Chambers from Arsenal on a season-long loan.
The promising guard, 21, turns into the most recent expansion to Aitor Karanka's squad having been dropped taking after Arsenal's 4-3 rout by Liverpool in their opening apparatus of the season.
Spaniard Karanka manufactured his notoriety for being a focal guard, and he told their official club site: 'I'm truly satisfied.