Mesut Ozil has slammed Chelsea for letting one of his former team-mates leave the club.
The former Arsenal playmaker scored 33 goals in 184 appearances for the Gunners and boasts a number of top trophies to his name including the World Cup.
Taking aim on social media, the 35-year-old claimed it was a huge mistake for the Blues to let his former international team-mate Antonio Rudiger join Real Madrid.
The Spanish giant is currently top of La Liga after they beat Mallorca 1-0 on Wednesday thanks to a goal from Rudiger.
Madrid's manager Carlo Ancelotti was full of praise for the German international after the game, stating: 'He has taken advantage of others' injuries. He is performing at a very high level, with continuity.
'He is always ready in duels. He is an insurance that we have behind. He is playing at his best.'
Responding to his comments on X, Ozil wrote: 'Prime Toni Rudiger is just the world's best defender at the moment. Incredible season for my former club Real Madrid. You can also ask Haaland or Osimhen how good he is!
'Look what has happened with Chelsea after he left … they are missing his mentality every day …'
Although Rudiger did leave Chelsea on a free transfer when his contract expired, the 30-year-old claimed the club were slow to offer him a new deal.
In an article he wrote for The Players' Tribune, he stated: 'Unfortunately, my contract negotiations had already started to get difficult last fall.
'Business is business, but when you don't hear any news from the club from August to January, the situation becomes complicated.
'After the first offer, there was a long gap of just nothing. We're not robots, you know?
'You cannot wait for months with so much uncertainty about your future.
'Obviously, no one saw the sanctions coming, but in the end, other big clubs were showing interest, and I had to make a decision.'