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.