Barcelona and Real Madrid face each other in the first El Clasico of the new season on Saturday.The El Clasico, always a feisty affair, will lack the usual electric ambience from the stands; in fact, it will be the first El Clasico to be played without fans owing to the COVID-19 pandemic. However, that only takes away a minuscule charm off the fixture because the Barcelona and Real Madrid rivalry is one of the most historic and fierce ones in club football.Both teams come into this game on the back of defeats in the La Liga. While Real Madrid succumbed to a shock home defeat against La Liga newcomers Cadiz, Barcelona were stunned by Getafe.While the Catalan club got back to winning ways in midweek in the UEFA Champions League against Ferencvaros, Zinedine Zidane’s side stuttered to another home defeat, this time at the hands of Shakhtar Donetsk.The King of #ElClásico pic.twitter.com/Pm4dS2uWLt— FC Barcelona (@FCBarcelona) October 22, 2020Considering the same, Ronald Koeman might feel optimistic in the buildup to his first El Clasico as the Blaugrana manager. However, despite losses in their two previous games, Real Madrid may not succumb as easily against Barcelona.In fact, the Merengues might as well have the upper hand in the first El Clasico of the season. On that note, let us have a look at five reasons why Barcelona might struggle against Real Madrid.#5 Unavailability of Marc-Andre Ter StegenMarc-Andre Ter Stegen is missing from the Barcelona team as he recovers after a knee surgery.Marc Andre Ter Stegen is undoubtedly one of the best goalkeepers in the world. What separates the German from the rest is his ability to be consistently good.Ter Stegen was one of the few bright sparks in the Barcelona team amidst the club's turbulence last season, and his assured presence at the back enabled the Blaugrana to weather a lot of storms.However, the German custodian is currently recovering from a knee tendon surgery and is unavailable for the game against Real Madrid. Ter Stegen would be a huge miss for Koeman, who will hope Neto to be up for the challenge in his first-ever El Clasico.Barcelona goalkeeper Marc-Andre Ter Stegen out for two months of action with tendon injury https://t.co/ywZ4hdNKxo— footballespana (@footballespana_) August 17, 2020#4 The Barcelona backline has already seen two red cards this seasonFC Barcelona vs Ferencvaros Budapest: Group G - UEFA Champions LeagueClement Lenglet almost cost Barcelona all three points in the La Liga game against Celta Vigo earlier this month.The Blaugrana were leading 1-0 when the Frenchman picked his second yellow of the game for a foul on Denis Suarez in the dying minutes of the first half to receive his marching orders.However, the Blaugrana rode the brilliance of Lionel Messi and managed to win the game 3-0. Nevertheless, Koeman has issues to resolve in his defence.Red Card to Pique, Who'll be suspended for the game against Juventus next week. pic.twitter.com/7kfQlgVLgl— Forza Juventus (@ForzaJuveEN) October 20, 2020Barcelona's defensive indiscipline also came to the fore in the Champions League game against Ferencvaros. What should have been a morale-boosting victory ahead of the game against Real Madrid has turned out to be a glaring reminder of Barcelona’s troubles at the back.This time, it was Gerard Pique’s vulnerability to pace that came to the fore. The centre-back was given a straight red for a lazy pull-back after opposition striker Tokmac Nguen had beaten Pique for pace.It was an incident that left a bitter after-taste in Koeman’s mouth but would have had Zidane licking his lips in glee. With a pacy attack, Real Madrid will be aware that they could use Barcelona’s nervy backline to their advantage.