Wirtz, 22, completed a 116-million-pound move from Bayer Leverkusen to Anfield in June and initially found the physical intensity of English football challenging.

Slot explained that the tailored programme was designed to help the German international better cope with the league's pace and physicality, an adjustment that now appears to be paying dividends.

After a steady but testing start to life on Merseyside, Wirtz has shown clear signs of improvement in recent weeks. He impressed in Liverpool's 2-0 victory over West Ham United in late November, before delivering another strong display in last week's 2-0 win against Brighton & Hove Albion.

According to Slot, those performances reflect a player who is beginning to find his rhythm in English football.

Slot's side will look to build on that momentum when they face Tottenham Hotspur on Saturday, with Liverpool aiming to extend their current run to six matches unbeaten.

The Dutchman believes Wirtz's growing confidence and physical adaptation are important factors as the Reds seek consistency during a demanding period of the season.

"Florian has improved a lot. I am not talking about his ability on the ball because we could see from the start that that was top," Slot told Liverpool Echo.

"But I saw in one moment against Brighton where he took the ball off Dom [Szoboszlai], he dribbled and a player came to him and he pushed him away and kept on dribbling. Then he provided a cut back cross for Hugo [Ekitike] who shot over the bar.

"Later he won the duel with (Brighton's) Jan Paul van Hecke that led to the counter attack with the shot from Mo [Salah]. In those moments you see it gets easier for him. It takes a lot, a lot, a lot of effort for him to play in this intensity but he is getting used to it. That is my take.

"Both [fitness and weight work]. A lot of them have grown in kilograms, in muscle. That's one thing. And secondly, if you are only in the gym you cannot be prepared for 90 minutes of Premier League football.

"It is about playing those games, I would say training but we hardly ever do that, so it's playing, playing, playing."

Mason Mount and Raphael Varane return to training for Manchester United