Shakhtar Donetsk boss Mircea Lucescu has confirmed midfielder Willian has left the club, with the Brazilian likely to join Anzhi Makachkala immediately.
Willian, 24, was strongly targeted by Premier League clubs Tottenham and Chelsea, but it seems a deadline day swoop from the big spending Russian side has triggered Shakhtar's hefty release clause.
Reports suggest Anzhi offered £35 million for Willian, making it the most lucrative deal of the January transfer window.
Lucescu conceded there was little Shakhtar could do to prevent the move, claiming Willian had much more to achieve in Ukraine.
"There is a club willing to pay the release clause in his contract and Willian agreed to move. There is nothing I can do," Lucescu said. "To tell you frankly, I tried to convince him to stay because I think his decision is hasty and not thought out well enough. He is like a son to me.
"He came to Shakhtar almost as a child and leaves us as a 24-year-old man. I told him he would have achieved more with us when we said goodbye. Why did he not listen to me? I guess he was under huge pressure from his agent and his relatives that wanted to get everything at once."
Willian will link up with striker Samuel Eto'o at Anzhi as Guus Hiddink's side close in on the Russian Premier League title.
Anzhi, who sit just two points behind league leaders CSKA Moscow, freed up some cash for the Willian deal with the sale of defender Christopher Samba to Queens Park Rangers.