#3 Ferland Mendy - Real Madrid
32-year-old Marcelo does not feature in our list of top five La Liga left-backs, mainly due to his struggles with injuries, but the rise of Ferland Mendy this season also played its part in the decision.
The French defender enjoyed a great season with Los Blancos after spending a year on the sidelines and has largely impressed with his lightning-quick pace, dribbling skills and pin-point crossing.
Though he only had one goal and two assists this season, his involvement in Real Madrid's buildup play was top-notch. The young left-back is likely to play a key role in the Champions League fixtures, with Marcelo out for the rest of the season.
#2 Pervis Estupiñán - Osasuna
Pervis Estupiñán had a breakthrough season at Osasuna, where he is currently on loan from Watford.
The 22-year-old left-back was an absolute beast for the club that finished 10th in the league on their return to the top flight. He was a rock in the defence for Osasuna and posted some impressive stats, averaging 2.3 tackles a game, 1.6 interceptions and 1.3 clearances a game.
Despite being so busy in the defence, he was one of their key players going forward and created a lot of chances from the wide positions. He attempted 37 crossed into the penalty area, a stat only bettered by Jesus Navas, who has 40. He had 1.2 key passes every game and as a result, ended the season with five assists for the season.
His contract with the Spanish club expires next summer and with Watford now back in the Championship, it would be better for his development if he stays at Osasuna for the next campaign.
#1 Sergio Reguilón - Sevilla
Real Madrid left-back Sergio Reguilon, who spent the 2019-20 season on loan at Sevilla, was one of the best defenders in the Spanish top flight this term and formed a formidable full-back partnership with Jesus Navas.
He displayed a lot of maturity in his performances, maintaining a delicate balance between pushing forward for a goal and staying back to defend against the incoming danger. His stats present a telling story as to how the young Spaniard proved himself equally comfortable on both ends of the pitch.
He won close to two tackles every game, made one crucial interception and 1.4 clearances a game on average. Interestingly, despite his modest physical stature, he was dominant in the air as well, winning 1.3 aerial duels per game.
The 23-year-old left-back contributed to six goals this season, scoring twice and setting up four goals for his teammates, while also averaging 1.3 key passes every game. His good reading of the game and impressive work-rate helped his side to the third-best defensive record in the league.
His loan spell at Sevilla will be over at the end of the season and with Mendy already filling in the shoes of Marcelo, it will be difficult for him to cement his place in the Real Madrid squad. Maybe another loan spell is in the works for him?