#4 Consecutive embarrassing eliminations from the Champions League
When Barcelona were drawn against AS Roma in the quarter-finals of the 2017/2018 Champions League campaign, many would have been forgiven for dismissing the fixture as an easy ride for the Catalans.
They were on a run of 13 matches without defeat in all competitions, while they had lost just one match all season (away to Espanyol in the Copa del Rey).
Things seemed to go to plan in the first leg when Barcelona posted a comfortable 4-1 victory and many saw the second leg at the Stadio Olimpico as nothing more than a mere formality.
However, in shocking scenes, a star-studded side led by Lionel Messi capitulated, leading to one of the most memorable comebacks in Champions League history.
Just like that, Barcelona were eliminated and their dreams of the treble were ended, although their triumphs in the league and Copa del Rey helped calm the storm.
Anybody who thought that Roma debacle was a one-off were in for a shock, as just a season later, Barcelona were on the receiving end of an even more improbable comeback in the semi-finals, with Liverpool defeating them 4-0 to overturn a 3-0 first leg deficit.
Calls for Valverde's sack were overwhelming in the aftermath of that Anfield disaster but even though he survived the axe, the reality that he oversaw consecutive embarrassing eliminations from the Champions League was a Sword of Damacles hanging over his head that was finally dropped in January 2019.