Bayern Munich midfielder Bastian Schweinsteiger rates Arsenal defender Per Mertesacker among the best in Europe.
Schweinsteiger - whose Bayern side face the Gunners in the Champions League last 16 on Wednesday - has hailed the impact of the giant stopper.
"Per has made them one of the most defensively solid teams in England - and they look to have addressed their problems," the Bayern midfielder told the Sunday Mirror.
"It was always going to take Per time to adjust to a new league.
"But now we see him for what he is which is one of the best central defenders in Europe with fantastic positional awareness and real leadership qualities."