Liam Rosenior says Mamadou Sarr's PSG mistake will benefit Chelsea defender as coach talks up his potential

Sarr was handed a massive show of faith on Tuesday evening as he made his Champions League debut in the second leg of Chelsea’s round of 16 tie. Starting against the reigning European champions, the Senegal international faced the ultimate test under the Stamford Bridge lights.

The occasion proved difficult for the youngster, whose early lapse in concentration allowed Khvicha Kvaratskhelia to open the scoring for PSG, sending the French side on to an 8-2 aggregate win. That strike effectively ended Chelsea's hopes of a European comeback, leaving the defender under the spotlight for all the wrong reasons in a season-defining moment.

Speaking ahead of the Blues' return to Premier League action, Rosenior emphasised that such setbacks are an essential part of a young player's education. He revealed that Sarr's response on the training pitch has been perfect, showing the mental fortitude required to play for a club of Chelsea's stature.

"I’ve worked with Mamadou for nearly two years and I'm so excited for his career – that's why he's here," Rosenior told, as quoted by the club's official website. "But sometimes you have to go through negative experiences to improve. He will come back. He trained very well [on Thursday] and he's a massive part of our plans moving forward."

Despite the pain of the PSG defeat, Rosenior believes the experience will ultimately accelerate Sarr's development. He insisted that the young centre-back has the necessary temperament to process the setback and use it as fuel to reach the levels expected of a Chelsea regular.

“We all make mistakes – me included – and you have to make sure you learn from them,” the coach added. “In the long run, the pain that he's gone through will make him an even better player. That’s where Mamadou is at in his career. If he learns from his mistakes, honestly, it's so exciting what he can become as a player.”

Sarr was loaned to Strasbourg by Chelsea last summer, but the Blues decided to recall him during the winter transfer window. He has made five appearances in all competitions so far and will be hoping for some playing time when Chelsea face Everton in the Premier League on Saturday.