And so, after two head coach sackings, a torrent of boardroom upheaval and the most discussed transfer request of all time, Barcelona return to the scene of the crime.

The scene in terms of the tournament itself, of course. But the memory of last season's Supercopa de Espana semi-final will be enough to bring many a Cule out in a cold sweat.

Barca led 2-1 going into the final 10 minutes of their encounter with Atletico Madrid, only to lose 3-2. Ernesto Valverde would never lead them again.

To say Valverde's sacking and its aftermath were shoddily handled would go some way to redefining the notion of understatement.

Club great Xavi was courted before deciding he would rather lead his boyhood club at a more agreeable time, one without mayhem spewing everywhere behind the scenes at Camp Nou.

Quique Setien took the reins and came to look out of his depth long before the 8-2 Champions League quarter-final defeat to Bayern Munich. Despite it being a game that caused shockwaves around world football, "8-2" still feels an utterly preposterous thing to type.

Sporting director Eric Abidal called out the squad for a perceived lack of effort during Valverde's final days, a somewhat belated show of solidarity with a coach he unceremoniously bundled towards the exit door.

Lionel Messi took umbrage and an unseemly public spat was still festering by the time LaLiga resumed following the coronavirus shutdown. Barca surrendered the title to Real Madrid before their night of shame in Lisbon.

Setien was gone and newly installed boss Ronald Koeman decided Luis Suarez should follow him through the exit door, something that did nothing to improve Messi's mood as he sought to prise himself away from Barcelona before being forced to stay under contractual duress.

A 2-1 defeat to Cadiz on December 5 left Barca seventh in LaLiga with 14 points from 10 games, with Koeman's dream job turning rapidly into a nightmare.

A listless 3-0 Champions League loss at home to Juventus followed, ceding top spot in their group. But since then, Barcelona are unbeaten in eight LaLiga matches, winning six, and Opta data suggests they might be in better health ahead of Wednesday's semi-final against Real Sociedad than at this time last year.

Creating more under Koeman

In 24 games under Koeman in all competitions, Barca have scored 53 and conceded 22, averaging 2.21 and 0.92 per game respectively in all competitions.

Heading into the semi-final with Atletico, Valverde's team were top of LaLiga with 40 points from 19 matches. That betters the 34 from 18 that Koeman's men have to lie third this time around, but it should be noted that leaders Atleti have 41 points from just 16 outings so far.

The numbers behind Valverde's final half-season at the helm hint at comparative progress under Koeman.

When the former Athletic Club boss led the Blaugrana during the period in question, they averaged 2.32 goals per game with 58 in 25.

However, that hugely out-performed an expected goals (xG) figure of 41.1, meaning they were getting out of jail a fair bit thanks largely to a certain special player. Koeman's Barca are in line with an xG of 53.66 this season, with shots per game up to 16.9 from 12.5 in the same period under Valverde.

Both men left their defenses grateful for wasteful finishing, with an xG against of 30.37 for Valverde and 29.83 for Koeman.

Messi still the master, Pedri and Griezmann stepping up

Despite a slow start to the season after his attempted exit, Barcelona's main man looks to be back up to speed.

In 21 games this term Messi has 14 goals, closing on the 15 from 19 in his final stint with Valverde as boss, when he hugely out-performed an xG of 9.83.

His importance to Barca remains paramount, leading the way in chance creation (51) as he did in the first half of last season (47).

Suarez was next on that list with 29 last time around. Although no one has filled the breach of 14 goals scored in the period by a man now spearheading Atleti's title charge, youngster Pedri has stepped up to craft 29 opportunities for team-mates.

Frenkie de Jong has created 25 chances from midfield - up from 19. The often maligned Antoine Griezmann has made the same leap, despite being on the pitch for 396 fewer minutes compared to last season. However, until he lifts considerably his goal and assist contributions from seven and four respectively, unflattering comparisons to Suarez and Neymar will remain.

There are numerous shafts of light permeating the gloom that descended upon Barcelona a year ago. Enough to justify the chaos of the interim period? Of course not, but there might be legs in the fragile Koeman-Messi axis yet.

Nevertheless, as Barca face up to Sociedad and Real Madrid prepare to take on Athletic Bilbao, it is hard to escape who this week's real winner will be.

A clinical 2-0 win over Sevilla on Tuesday put Atletico four points clear at LaLiga's summit with two games in hand. Diego Simeone's men will have enjoyed the Barcelona demise they triggered; this time they get to put their feet up for eight days and enjoy their fellow heavyweights punching holes in one another.