Nacho Monreal
Although Nacho Monreal was signed as emergency cover for an injured Kieran Gibbs in 2013 and initially struggled with confidence, the Spaniard has moulded into one of our best and most consistent players and arguably the best left-back in the PL this season.
Gibbs hasn’t managed to get back in the team since then and his deadline-day signing has proved a masterstroke from Arsene Wenger.