Diego Simeone believes Vinicius Junior has made "enormous" strides, as the Real Madrid star looks to inflict more derby misery on Atletico Madrid on Saturday.
Vinicius scored twice as Madrid thrashed Liverpool 5-2 in the first leg of their Champions League last-16 tie at Anfield on Tuesday, taking him to 18 goals for the season.
The Brazilian has saved some of his best performances for meetings with Simeone's Atleti, scoring in January's extra-time Copa del Rey win and starring in a 2-1 away triumph in the teams' last league clash in September.
Speaking at a press conference to preview Saturday's trip to the Santiago Bernabeu, Simeone was full of praise for the in-form winger.
"I think his growth has been enormous," Simeone said of Vinicius on Friday.
"It was a great bet that Real Madrid had on him, he improved all of his numbers year after year, and he's in a great moment as a player."
Saturday's game will see Simeone claim the outright record for the most matches as coach of one club in LaLiga history, as he oversees Atleti for the 425th time in the league.
Meanwhile, Simeone's 612th game with Atleti will see him draw level with Luis Aragones as the coach to have led them in the most competitive fixtures.
The Argentine puts his longevity down to the application of those who have played under him, saying: "Above all, I am lucky, and I have to be grateful to the club and to all those who played for the team.
"Without all these situations, both for the club and for the players, it would be impossible to meet these numbers; they made me able to express myself.
"The numbers are accompanied by the results. I'm grateful to all the players who went through the team. I am in the place I want to be, and I am still very excited."
While Atleti's six-game unbeaten run in LaLiga is their longest of the season, they sit 10 points behind second-placed Madrid in the table and look destined to endure a trophyless campaign.
Simeone, however, is adamant they have much to play for, adding: "There are seasons where we can compete to win something and others when it seems far away.
"It is not less important, what we have left. Every match where you put on the Rojiblanco shirt, you have to be excited."