Cech completed his move across London on Monday for a fee believed to be around £10 million, with the 33-year-old signing a long-term contract at the Emirates Stadium.
Mourinho openly stated that he did not want the Czech Republic international to leave Stamford Bridge – especially to a major Premier League rival – but has now acknowledged that he could not stand in Cech’s way, with the goalkeeper having fallen behind Thibaut Courtois in the pecking order.
“Petr has been a great servant for Chelsea for 11 years and helped this club to win almost everything there is to win,” he told the club’s official website.
“I always said I wanted him to stay but I understand Petr needed to move on to play first-team football every week.
“Sometimes you have to respect the wishes of someone who has earned so much respect with his service and actions for your club. I support [Roman Abramovich’s] decision to honour the player in this way.
“Petr’s success at this club will always to be remembered and we thank him for everything he did.”