Teenage goalkeeper Thibaut Courtois claims he has passed a range of fitness tests at Chelsea with flying colours after returning temporarily from his loan spell at Atletico Madrid.
The 19-year-old, on a season-long loan deal at the Vicente Calderon, has established himself as the club's first-choice keeper over Sergio Asenjo following the summer departure of David de Gea to Manchester United.
Courtois, who arrived at Chelsea from Genk in July and was sent straight out on loan, has returned to West London during the Primera Liga winter break.
The Belgium international was in the stands at Stamford Bridge during the Blues' Boxing Day draw with Fulham and has also undergone a range of tests, which he claims to have breezed through.
"The tests showed that over six months I have become a lot stronger," Courtois told Voetbal Primeur.
"I can jump a foot higher than I could last year and my reflexes have also improved.
"Chelsea were especially impressed by my results in the stress test. Under great pressure I was able to continue coolly."
While Courtois has impressed at Atletico so far, the teenager knows he faces a challenge in proving himself to new coach Diego Simeone, who was unveiled by the club last week.
"For now they are satisfied in all respects," he added. "Now we will see how the situation with Atletico's new coach plays out.
"I have to prove myself again against the other goalkeepers."