LaLiga 2019/20: Barcelona begin title defence with defeat to Athletic Bilbao
This was Barça's first Liga defeat on the road since a 0-2 reverse at Celta Vigo in May.
Without their talismanic captain Lionel Messi who is yet to recover from a calf injury, Barcelona looked largely bereft of ideas in attack despite handing a competitive debut to forward Antoine Griezmann at San Mamés.
The new €120 million signing could have had a goal on his debut but fired wide six minutes from time.
The Catalans twice hit the post, through Luis Suarez and substitute Rafinha respectively, but failed to breach a determined Bilbao rearguard.
Their profligacy was to be punished when Bilbao's Aritz Aduriz, on the field as an 88th-minute substitute, rolled back the years with a spectacular overhead kick that beat the Barça keeper Marc-Andre ter Stegen in the 89th minute. The home side then held on for their first Liga victory in six years against the defending champions.
The 38-year-old Aduriz in the process became only the second player ever to score in 15 successive league seasons, the first being Barcelona's Lionel Messi.
In a worrying sign of their over-reliance on Messi, the all-time highest scorer in LaLiga, the defeat at Bilbao marked the Catalan club's sixth straight game without a win in all competitions in the absence of their Argentinian captain - a span which includes a 1-1 draw at Serie A club Internazionale in the Champions League, 1-2 and 0-2 league defeats at Levante and Sevilla respectively, a goalless draw at Huesca and a 0-2 reverse at Celta Vigo.