Diego Simeone believes Atletico Madrid need top scorer Antoine Griezmann in top form if they are to once again derail city rivals Real Madrid's La Liga title challenge on Saturday.
Real hold a two-point lead over Barcelona at the top of La Liga and have a game in hand as they edge towards a first title in five years.
However, Atletico have won a record three consecutive La Liga clashes between the sides at Real's Santiago Bernabeu.
"We need the best of Antoine," said Simeone on Friday.
Griezmann scored the winner as Atletico won 1-0 at the Bernabeu last season as part of a spectacular 2016 for him on a personal level. He top scored at Euro 2016 and finished third behind Cristiano Ronaldo and Lionel Messi in the Ballon d'Or.
However, with success has come attractors and Griezmann is constantly having to distance himself from speculation over a move at the end of the season with Manchester United leading the chase for his signature.
"I always want the best for footballers who give their all like Antoine," added Simeone, who has committed himself to remaining in charge for Atletico's move to a new 67,000-capacity stadium next season.
"He has improved enormously because he wanted to and he has looked to improve."
Griezmann has scored 79 goals in 149 games for Atletico since joining from Real Sociedad for 30 million euros ($32 million) in 2014.
And any move away from Madrid in the summer will almost certainly require the buying club to pay his 100 million-euro buyout clause.
"He wanted to integrate himself into this club, which is different from the one he came from.
"He has transformed from a boy into a man on the field and taken important decisions.
"He is on course to consistently be among the top players in the world."