• Belgium goalkeeper has three years remaining on contract • ‘I do not say yes, I do not say no. I do not know’

Thibaut Courtois refused to give any assurances when asked about his long-term future while on international duty with Belgium. The 23-year-old, who has been linked with a move to Real Madrid, admitted Chelsea unexpectedly troubled season had changed him, and was diplomatic when asked if he would leave Stamford Bridge in the summer.

Asked if he will remain with Chelsea beyond the end of the season, Courtois said: “I do not say yes, I do not say no. I do not know. I still have three years on my contract. We must see what Chelsea want. It is true that it [this season] has changed me. Until now I had always won a trophy every season. We hope that next season will be better.”

Courtois, who missed several weeks of the campaign after undergoing knee surgery in September, insisted he has never doubted his ability even in testing times.

“Especially mentally, you have to be strong,” said the former Genk goalkeeper, whose sister and both parents have all played volleyball at a high level. “But with my character, and having grown up in a family of top athletes, I do not have too many problems with it. I never doubt.”

Courtois is away with Belgium preparing for Tuesday’s friendly against Portugal – a fixture that was switched to Leiria having initially been cancelled for security reasons in the wake of the Brussels terror attacks – and he believes he is training at a higher standard with his international colleagues than when with his club. “The level of training is higher among Devils,” he said. “There are only world-class players [here], while at Chelsea, there are some players a little less rated and we often train with youngsters as well.”

Courtois is one of a host of Premier League-based Belgium stars to have suffered injury-plagued seasons, along with his Chelsea team-mate Eden Hazard, the Tottenham defender Jan Vertonghen and the Manchester City pair Vincent Kompany and Kevin De Bruyne.

And that is not something that has come as a surprise to the former Atlético Madrid loanee. “We have matches every three days, no winter break, there are many cup matches,” he said. “The pace is high and the contacts are tough.”