Thibaut Courtois is sure that Chelsea need to spend big to compete in the Premier League next season.
Asked if Chelsea need a big summer to add players in order to challenge for the title, Courtois said: "Yeah, I think so. I think especially if you see how City and United are spending and working.
"I think if we want to aim for the top, we should do the same - obviously within the limits of what's possible as well.
"I think that the transfer market has gone pretty crazy. Nowadays you pay £80m for a defender I think - that's crazy figures.
"We'll see what's going on and I am sure the board will do what needs to be done."