Hundreds of German fans gathered in support for Mesut Ozil on Monday after he quit international football, citing "racism and disrespect" over his Turkish roots.
Supporters gathered in Berlin on Sunday wearing 'I am Ozil' T-shirts, waving Turkish and German flags in solidarity with the Arsenal midfielder.
He said last week he received hate mail and threats, and was blamed for Germany's disappointing World Cup, reports BBC.
Germany's football association "rejected" allegations of racism.
However, it said it could have done more to protect him from abuse.
Ozil, 29, was criticised after being photographed with Turkish president Recep Tayyip Erdogan in May.
In announcing his international retirement, he said: "I am German when we win, but I am an immigrant when we lose."
Former Germany striker Fredi Bobic, who is now the Eintracht Frankfurt sporting director, criticised the manner of Ozil's international retirement.
"I think that's a bit cowardly," he told German newspaper Bild am Sonntag.
"Ozil's criticism of social media, especially in the direction of the German Football Association (DFB), is unbearable.
"This blanket charge of racism simply does not correspond to reality. He could have given an interview somewhere, live on TV.
"For us footballers, the rule is 'be a man and stand up.'"
Ozil, a third-generation Turkish-German, was born in Gelsenkirchen and was a key member of his country's 2014 World Cup-winning side.
He thanked fans for their "love" during the Gunners' pre-season tour, and has received backing from his team-mates and new manager Unai Emery.
