One defeat is certainly no reason for everyone to lose their minds but, when defeat is as rare as it is for Barcelona, questions are inevitably going to be asked.
Doubts will especially arise when defeat is a 4-1 loss away at a team who generally finish around mid-table.
Only time will tell whether Barca's defeat to Celta Vigo on Wednesday night was a one-off or a sign of things to come.
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The manner in which they lost would have been the concern for fans and management alike; where was the fluidity and skill we're so used to watching? The defence looked shaky and the midfield looked lightweight - Sergi Roberto proved he is no replacement for the increasingly irreplaceable Ivan Rakitic in midfield.
Compared to Chelsea's start to the season, Barcelona have nothing to worry about, yet the Catalans are still uneasy. There have been rumours of unrest between Luis Enrique and star players for months now: there were mutterings of discontent last season as well but the treble quickly silenced any doubters.
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The problem is, if there is tension between Enrique and the players, most notably Lionel Messi, then the future of Luis Enrique looks untenable. They say that no player is bigger than the club, however, without question Lionel Messi is currently bigger than Barcelona. They need him more than he needs them and he knows it - it puts him in a very powerful position.
History repeating itself
It would be a huge surprise if the defeat to Celta Vigo was a marker for the rest of season, but perhaps it shouldn't be such a shock. No team from La Liga has been able to retain the league title for the past five seasons, why should this season be any different? Obviously Barcelona are a fantastic side, but even the best teams feel the pressure.
After their double in 2010/11 season, Barcelona looked set to dominate the following season - yet they finished nine points behind a rampant Real Madrid. Confidence and form in football doesn't often last longer than a season; Manchester City failed to retain the league title after the two times they managed to capture it. Maintaining excellence can become very tiresome.
Real Madrid were almost written off this season after the appointment of Rafa Benitez, however, they are currently embarking on an impressive run of form. Wednesday's victory over Athletic Bilbao took them to the top of the league - maybe Benitez isn't that bad after all.
Much like their city rivals, Atletico Madrid are also enjoying a fine start to the season, they've even got Fernando Torres firing. The Spanish international has scored twice already this season and got an assist to his name; with Atletico's watertight defence still intact, they seem to have the balance just right.
Despite Real and Atletico's good starts, you can't help but feel the title is Barca's to lose. They have the stronger squad and the better players, whether they keep up their high level all season will be dependent on their mental strength as opposed to a lack of ability. It may also depend on Luis Enrique's ability to keep Lionel Messi from losing faith in him.