 When new coach Massimiliano Allegri was appointed in the summer of 2010, he kept Antonini at the left back position and Luca was a regular in the starting XI for the whole of the 2010–11 season, helping Milan win their 18th Scudetto.He continued to be a regular for the 2011–12 season, where Milan disappointingly finished second to Juventus, but managed to win the Supercoppa Italiana in the summer of 2011.At the start of the 2013–14 season, Antonini left Milan to join Genoa as part of a deal which saw midfielder Valter Birsa move the other way.