Barcelona squad may be Luis Enrique's undoing this season
Erring on the side of caution tends to be a sound strategy when drawing conclusions from early-season games, but with losing 4-0 an incredibly rare occurrence for Barcelona, the events of the last week merit special attention.
Prior to Athletic Bilbao's magical night at the San Mames, the last side to put four unanswered goals past Barcelona was Jupp Heynckes' treble-winning Bayern. Sevilla hadn't scored four against them since 1995 before their 5-4 UEFA Super Cup defeat on Wednesday.
The season may be young, but there are already hints of problems that could be costly for Luis Enrique further down the road.
A significant part of Barcelona's treble win in 2014-15 was the impeccable fitness they brought to the crunch stage of the season; their optimal physical state made possible by heavy rotation prior to Christmas. Deviation from that plan is unlikely this year, particularly when new signings will enter the fray and add quality in January. But in order for the approach to work, squad players need to help keep Barca alive until the turn of the year.
The big question is whether the players on this year's squad are good enough to deliver. Is a midfield without Xavi strong enough to give Ivan Rakitic valuable rest without sacrificing good results?
On the evidence of the last week, perhaps not. With midfield substitutions costing Barcelona their control in the UEFA Super Cup against Sevilla, Luis Enrique invested a huge amount of trust by going on to start Javier Mascherano, Rafinha Alcantara and Sergi Roberto together against Athletic. His faith wasn't repaid.
Rafinha had one of his poorest games since becoming a first-team member, showing little of the bravery on the ball and imagination for which he earned a return to the Camp Nou.
Sergi Roberto, meanwhile, had a second consecutive weak game when handed a rare chance in the attacking midfield position he should theoretically be best suited for -- suggesting his lack of influence upon coming off the bench against Sevilla was not anecdotal.
While there is no such thing as a direct replacement for Xavi, a quality midfielder like Rakitic is capable of wriggling out of trouble and using the eagerness of opponents to his advantage, giving his team time to breathe.
Sergi Roberto floundered on Friday, conceding the ball easily and showing little spatial awareness when put under pressure. It will be intriguing to see if Luis Enrique persists and offers his former Barca B pupil another chance to play in attacking midfield going forward, or whether he now has enough evidence that the youth graduate doesn't fit the bill.
Barcelona's problems don't stop in the middle. Jeremy Mathieu was criminally negligent in his defensive duties in the European Super Cup, leaving Jose Antonio Reyes unmarked for the Sevilla's second.
The defensive problems also appeared against Athletic; individual errors among the back four contributing to three of the four goals. While the risk involved in pairing Dani Alves and Adriano is nothing new, slack showings from the central defensive duo of Marc Bartra and Thomas Vermaelen on Friday will be of greater concern. The Belgian's lack of competitive football in the last 12 months can at least partially explain his slow reaction time to danger in the box, but Bartra has no such excuse.
Whether against Ciro Immobile or Aritz Aduriz, Bartra has regularly come up short in shoulder-to-shoulder battles with strikers over the course of the last month, lacking the authority and assertiveness that makes Gerard Pique so vital in correcting the mistakes made by Barcelona's risk-prone full-backs.
The treble winners appear to have greater depth in defence than in previous years. But with Bartra and Vermaelen questionable and Mathieu always capable of a costly slip-up, Pique and Mascherano still remain their best defenders by quite some distance. What happens if one gets injured?
Should Pedro opt to leave his boyhood club in the coming weeks, the gap in quality between starting and squad players will be greater in the forward line. The Spain international's exit would mean that until Christmas, instead of having a multiple Champions League winning striker on the bench, Barcelona would be forced to look to a pair of attacking players whose experience at the highest level is a handful of first team games.
Sandro Ramirez and Munir El Haddadi have raw talent in abundance, but asking them to bare the huge creative weight placed on Barca forwards may be too much at this stage in their career. It is little wonder
Pedro's teammates badly want him to stay -- they know their success could rely on big goals and performances from the second choice forwards in the first half of the season.
Luis Enrique has chosen to put an optimistic spin on the San Mames game, downplaying it as a freak result caused by a combination of few training sessions and a gruelling preseason travelling schedule.
If Barcelona go on to dispatch Athletic at the Camp Nou, then in all likelihood supporters will follow the party line. But with the Super Cup result not isolated and instead following the European Super Cup as well as preseason matches where squad players choked, something of greater significance looks to be bubbling beneath the surface.
With Real Madrid, Atletico Madrid, Valencia and Sevilla all strengthening -- not to mention European rivals also adding new quality -- Barcelona will need to be sharper than ever this year to maintain their winning pace. Their squad may not allow that.
Lee Roden is a European football writer based in Barcelona. Follow him on Twitter: @LeeRoden89.