Barcelona began their 2017 campaign with a defeat after going 2-1 down to Athletic Bilbao in a Copa del Rey round of 16 first leg tie at the San Mamés Barria stadium on Thursday.
Aduriz scored after 25 minutes to put the home side in the driving seat with Williams completing a first rout three minutes later as a star studded Barcelona lacked any form of response.
Luis Enrique's men returned after the break with a better performance that saw them reduce the deficit seven minuets after the restart through the ever dependable Lionel Messi.
Barca were full-strength against Athletic, who were without Oscar de Marcos and benched Iker Muniain, and had recent Copa history on their side after victories over Los Leones in the last eight last season and both the 2012 and 2015 finals.
Yet it was Athletic who dictated the tempo early on and could’ve scored in that time as a header from a corner went just wide, before Marc-Andre ter Stegen tipped another ball around his post.
Gerard Pique came even closer at the other end, however, when he beat Gorka Iraizoz to a delivery in the Athletic penalty area but couldn’t guide his header on target and was then taken out by the goalkeeper.
Still, Athletic managed to capitalise on a quick counter through Aritz Aduriz, who headed past Ter Stegen at the German’s near post, marking the veteran’s first goal from open play since November.
Aduriz was lucky to stay on the pitch after that as referee David Fernandez Borbalan failed to see him lash his elbow into Samuel Umtiti’s throat. It would’ve been a certain red for the Spaniard, had the official spotted it.
The referee consequently began dishing the cards out like it was still Christmas as Neymar was somehow not awarded a penalty on the cusp of half-time after he was clearly tripped by Xabier Etxeita.
Regardless, it didn’t stop Lionel Messi from notching up his 20th goal in 29 matches against Athletic shortly after the restart.
The Argentine flighted a free kick that Iraizoz pushed onto the bar and desperately tried to scramble away, but the ball had crossed the line.
With that, Barca finally had the initiative and forced Athletic into submission. Aduriz stayed down after taking a blow to his chest from Luis Suarez, but it didn’t deter Barca as Neymar swerving shot was tipped over by Iraizoz.
The hosts then went down to 10 men. Raul Garcia left his studs in Neymar’s heel and subsequently saw yellow for the second time in the match.
He was soon joined – and out of the second leg – by Ander Iturraspe, who became the second Leones player to be dismissed after a foul on Neymar from behind.
Barca unsurprisingly dominated the final 15 minutes and brought on Paco Alcacer for a four-man attack against Athletic’s nine.
Their best bet was another Messi goal, the No 10 collecting Jordi Alba’s low cross from the left and shimmying past one, but instead of shooting for 2-2, he took a second man on and was eventually dispossessed at the last moment.
And with seconds remaining, Messi’s half-volley cracked the post with Alcacer missing the rebound.
Barcelona will now turn their attention to this weekend's La Liga fixture against Villarreal away from home on Sunday before returning home for the second leg Cup tie against Bilbao next Wednesday.Athletic Bilbao XI:
Iraizoz; Boveda, Etxeita, Laporte, Balenziaga; San Jose, Iturraspe; Saborit, Garcia, Williams; AdurizBarcelona XI:
Ter Stegen; Sergi, Pique, Umtiti, Alba; Rakitic, Busquets, Iniesta; Messi, Suarez, Neymar