Defender Christopher Jullien should aspire to "get close" to Ballon d'Or nominee Virgil van Dijk, says Celtic manager Neil Lennon.
Jullien, 26, has been a revelation at centre-half since joining from Toulouse in the summer and scored the winner against Lazio in Thursday's Europa League victory.
Netherlands international Van Dijk spent two years at Celtic and is now a Champions League winner with Liverpool.
"Virgil is the benchmark," Lennon said.
"At [Jullien's] age, he has his best years in front of him. Since he has settled, he has been absolutely outstanding with similar attributes to Virgil.
"He has to look at that and say 'how close can I get to that?' and there is no doubt he can improve and take his game on and there is that willingness from him to do so.
"His professionalism is fantastic and his attitude since he came through the door has been brilliant."
As much as Jullien's influence delivered a dramatic late winner in Glasgow for Lennon's side, the intervention of Fraser Forster to preserve that lead in the dying embers was even more impressive.
The England international goalkeeper pulled off a world-class save deep into injury time to deny Danilo Cataldi's rasping shot from range for Celtic to hold on.
Since moving to Glasgow in the transfer window on a season-long loan from Southampton, the 31-year-old has kept four clean sheets for the Scottish Premiership leaders.
Forster is contracted at St Mary's until 2022 and Lennon was coy about the possibility of him prolonging his Parkhead stay beyond the summer.
"I am grateful to have him here and to Southampton for letting me bring him in," he said. "I think he is glad for the opportunity we have given him to play regular football again and you can see what he brings to the team.
"The two saves were crucial. People talk about the save at the end, but I think the block from Parolo was so pivotal to us winning the game.
"He has proven in his first spell here what he is capable of and has shown again why he is such a renowned goalkeeper.
"Whether we can get him on a permanent basis all depends on what Fraser wants to do and what Southampton want to do - but we are a long way off talking about that just yet."