#1 Poor away form in the Champions League

Barcelona have struggled away from home in the Champions League for the past couple of seasons. The Catalan club has twice in the past three seasons dissolved a first leg home win; against Atletico de Madrid in 2016 and against AS Roma in 2018.
The last time Barcelona won an away game in the knockout stages of the UEFA Champions league was in 2016 when they defeated Arsenal 2-0 at the Emirates stadium. Such poor away form in the Champions League has made Barcelona vulnerable to early knockout stage exit from Europe's elite club competition.
The club showed signs of improvement when they defeated Tottenham 4-2 at the Wembley stadium earlier this season; however, the club once again had lackluster performances against Inter Milan and PSV Eindhoven away from home.
Barcelona will need to work extensively on their away form if they want to have any chance at lifting the Champions League trophy this June.