Representatives from both north London rivals were present to see Werder draw 0-0 with Hamburg, but both Arsene Wenger and Harry Redknapp believed to be eyeing January moves for Marin.
The 20-year-old is bring talked up as the next big thing in German football, with Wenger in particular keeping tabs on his progress now for over a year.
Acorrding to reports in Germany, full international Marin, who had previously been linked with Manchester United, could cost around £15million during the new year transfer window.
Zinedine Zidane has dismissed the suggestion that Gareth Bale may be unhappy at Real Madrid.
Despite being restricted to just four appearances since moving to Celtic, Jack Hendry insists he is constantly improving his game.