Real Madrid's Sergio Reguilon has had a meteoric rise since Santiago Solari took charge at the Spanish capital. From being a fringe player under Julen Lopetegui, the 22-year-old has gone on to displace Marcelo as the first-choice left back.
Interestingly, Real Madrid has won only once and lost six in the previous nine La Liga matches when Marcelo has started.
The Brazilian's defensive capabilities have been under the scanner since the early stages of this season and Reguilon has made the most of this opportunity. As per statistics from Wyscout, the Spaniard has made more interceptions per game (4.9) than Marcelo (4.16). He has made more clearances per game (1.89) compared to Marcelo (1.27). He has also been better in one-on-one situations, winning 7.57 of his duels per game compared to just 5.7 for the experienced Marcelo.
In Marcelo's last league appearance against Girona, he was given a run for his money by Cristian Portu. The winger regularly got behind him and even for the winning goal, the left-back was at fault for allowing him to have a free header at the far post.
Whereas, Reguilon has shown great poise in balancing his offensive and defensive duties. He contained Angel Correa against Atletico Madrid and was equally competent going forward with the ball to combine with Vinicius Junior on the left flank.
His passing accuracy in the final third (73.6%) is better than Marcelo's (71.3%), but the latter has outshone him when it comes to crossing (33.4 % v 31.8%) and shooting at goal (1.07 v 0.88).
Against Ajax, the Castilla product will have his hands full as he will not have Sergio Ramos leading the defence. The combination of Noussair Mazraoui and Hakim Ziyech on Ajax's right-hand side created enough problems for Madrid in Amsterdam and the duo will once again look to inflict maximum damage in a bid to overcome a 2-1 deficit in the first leg.
The youngster's performance will be key for Madrid when Ajax come calling!