Eden Hazard is Chelsea's greatest foreign player, says assistant manager Gianfranco Zola.
The Belgium international has been at Stamford Bridge for seven years, winning two Premier League titles, an FA Cup, the Europa League and an EFL Cup since joining from Lille.
Chelsea have boasted stars including Didier Drogba and Zola himself in the modern era but the Italian says Hazard, who has been linked with a summer exit to Real Madrid, is the pick of the bunch.
"Eden Hazard's definitely at the very top," said Zola, ranking the 28-year-old as Chelsea's best overseas signing.
"He's such an unbelievable player. The more I've spent time with him the more I appreciate him as a player, but also as a boy.
"He's been great. I would love to have him for longer. What we are trying to do here perfectly suits him. It's no coincidence that he's having his best season.
"I don't want to take anything away from him and what he has achieved. But certainly, the way we play helps him a lot.
"Of course we hope that Hazard will stay with us because he's such an important player for us."
Zola said Chelsea’s season, littered with controversy and rumours over manager Maurizio Sarri's future, could still be judged a success if they can win the Europa League and finish in the top four of the Premier League.
"There's a lot of talking around this team, I realise that," added Zola. "But we as coaches have to make sure we are not distracted by all of that.
"We need to maintain focus, because this year a lot of times I heard talk that it's been a bad season.
"But if we can reach the final and maybe win the Europa League and end up fourth in the Premier League, I think it could be a remarkable season."
Chelsea look to confirm their place in the Europa League semi-finals when they host Slavia Prague on Thursday, holding a 1-0 lead from the first leg.