Luciano Spalletti has warned that he will quit unless the Zenit St Petersburg hierarchy allow him to bring in more players now that his team have reached the UEFA Champions League knockout stages.
It is the first time that Zenit have managed to reach the last 16 of Europe's premier club competition, where they will be joined by fellow Russian club CSKA Moscow.
It has been hailed a great achievement, but Spaletti insists that his side need to sign some big name players if they are to continue to succeed.
He said: "I really enjoy St Petersburg and I'd like to continue my work here.
"But to continue our progress we need to strengthen with at least a pair of top-class players. We must go ahead otherwise I will have to resign. It's about time we purchased really classy footballers."
Zenit progressed after drawing with Porto in Portugal on Tuesday, while CSKA also qualified after defeating Inter Milan 2-1 the following night and Moscow boss Leonid Slutsky was delighted with his team's performance.
"Inter are a very strong team and it's extremely hard to take them on," Slutsky told www.gazeta.ru. "And it makes our win even more precious."
Slutsky hailed CSKA striker Seydou Doumbia who led the attack, whilst his team-mates Tomas Necid and Mark Gonzalez were sidelined with injuries, the Russian added: "I believed in our success up to the very end.
"My team showed they also believed in me. Together we clinched the needed result. I'm really happy now. The result of the match with Inter has changed the outcome of our season to the better.
"We suffered misfortunes, injuries and unexpected losses throughout the entire season. But we kept on fighting and won a place in the Champions League play-offs. I think it's a good end to the long season."