Chelsea goalkeeper Thibaut Courtois has hit back at former Manchester United manager Louis van Gaal following his criticism of the Belgian's performance during the Champions League last-16 tie with Barcelona.
Lionel Messi twice put the ball through the legs of Courtois at Camp Nou as Barca pulled off a 3-0 victory in the second leg, with the opening goal coming from a tight angle after only three minutes.
Van Gaal described the error as a "big blunder", but Courtois has suggested that the Dutchman is not qualified enough to pass judgement on his goalkeeping ability.
"When I hear so-called experts talking, I think they know nothing about goalkeeping," he told reporters.
"Van Gaal, for example, such people should not talk about goalkeepers. I know that I am doing well and I am growing to be in top form for the World Cup."
Courtois is currently on international duty with Belgium, who face Saudi Arabia in a friendly on Tuesday night.