Chelsea fans have been urged to be patient with €100m signing Mykhaylo Mudryk.
The January arrival from Shakhtar Donetsk has struggled to make an impact with the Blues.
But Ukraine caretaker boss Ruslan Rotan has backed the winger to improve next season.
Speaking to the press ahead of their Euro 2024 qualifier against England on Sunday, the 41-year-old said: "Mykhailo is a great talent and fulfilling his potential is right ahead of him.
"In a couple of months' time he will play a key role in the Premier League. He's one of the diamonds in our team and we cherish him. He's very motivated to play at Wembley. He's one of the key players.
"It's very positive and we look forward to his future with great optimism."