Under no circumstances should Barcelona lose at home to a newly promoted team. Sometimes, however, these things happen: Pep Guardiola's great side were beaten by Hercules on September 11, 2010 and almost exactly five years later, Luis Enrique's men went down to Alaves.

It was one of those fixtures that coaches just want out of the way. After the international break, with Lionel Messi and Luis Suarez tired, the Argentine not fully fit and Neymar only just back following his exertions with Brazil in the Olympic Games and their World Cup qualifiers, Luis Enrique was also without the injured Marc-Andre ter Stegen and has a Champions League game against Celtic to think about on Tuesday.

That gave the Asturian a selection dilemma and he decided to leave out both Messi and Suarez. Neymar started and there were debuts for recent signings Paco Alcacer and Jasper Cillessen. Gerard Pique and Sergi Roberto were also rested, while Jordi Alba and Samuel Umtiti were left on the bench.

Barca's first-choice back line these days is arguably composed of Ter Stegen, Alba, Pique, Umtiti and Sergi Roberto. But none of them started on Saturday and instead, Luis Enrique opted for the unconvincing partnership of Jeremy Mathieu and Javier Mascherano. Neither, it is worth remembering, began their careers as central defenders.

Mathieu headed home from a corner just after the break to make it 1-1, but the Frenchman missed an open goal shortly afterwards and was late tracking back as Alaves stunned Barca with their second goal on 64 minutes. Mascherano flapped at an attempted clearance in that move, while Aleix Vidal was also at fault - just as he had been for the first goal - and Cillessen perhaps could have done better with both strikes.

The former Ajax goalkeeper has only been at the club for a few days and it may have been an error to start him in this match, particularly with a completely changed defence in front of him. The Dutchman will take time to adapt and also learn the language, so it would perhaps have been better to opt for Jordi Masip - a player often praised by Luis Enrique who knows his team-mates well and also featured in pre-season.

Of course, none of that should really have mattered. Barca at Camp Nou are accustomed to blowing away their rivals and even with the changes, they should have had enough to wij. But Sergio Busquets and Denis Suarez were below their best in midfield, while Alcacer barely had a sniff on his debut and dragged a shot wide when an opportunity finally arrived in the second period.

Alcacer may well go on to be a successful signing for Barca but with Messi and Suarez left out of the starting line-up, the player the Catalans allowed to leave who was already adapted to their style of play, Munir El Haddadi, may have been more useful. For the new man, it will take time to adapt.

"It wasn't a good day from the start and we lacked precision," Luis Enrique said afterwards. "I am the one responsible for the bad things that happen. I know it and I accept it."

And he was right about that this time. Rotation is essential over a long season, but there were too many changes on this occasion. Some were enforced and leaving Messi and Suarez out until late on was understandable, but picking that defence appeared an unnecessary risk and so it proved. So while it is only one defeat, it could very well have been avoided with a different team selection.