Bayern Munich midfielder Bastian Schweinsteiger has hailed Per Mertesacker's contribution to Arsenal's impressive form this season.
The 29-year-old Germany international will face his compatriot during the two sides' Champions League last-16 first-leg clash at the Emirates Stadium on Wednesday.
"For many seasons Arsenal have been admired across Europe for their attacking play – but perhaps where they sometimes let themselves down was in defence," The Mirror quotes him as saying.
"Per has made them one of the most defensively solid teams in England – and they look to have addressed their problems.
"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."
Defender Mertesacker joined Arsenal from Werder Bremen in the summer of 2011.