The Basque Country derby began with both teams trying to assert themselves into the match before Bilbao striker Gorka Guruzeta forced Alex Remiro to make a good save from a solid header in the 21st minute.

The visitors ramped then up the pressure as Mikel Oyarzabal (21') missed the target by inches before Pablo Marin had his shot saved two minutes later.

In the 36th minute, a Jon Martin headed effort forced the home side goalkeeper Alex Padilla to make a good low save before Athletic got their next on target five minutes later after a hopeful attempt from Robert Navarro was easily gathered by Remiro.

Controversy arose shortly before half time when a Duje Caleta-Car header hit the arm of Athletic defender Aymeric Laporte but the referee did not award a penalty.

Sociedad started the second half brightly with Oyarzabal's attempt saved by Padilla and Marin striking the post on the rebound within the first minute of the second half.

Pellegrino Matarazzo's side deservedly took the lead in the when Carlos Soler threaded a pass to Guedes, whose shot was redirected into the net by Benat Turrientes (62') from close range.

The home side threatened for the last 20 minutes but could not find a breakthrough as Sociedad held on for an important lead heading into the second leg in three weeks.

"Very positive, boys performed very well today in all phases of the game, said Matarazzo to RSTV after the match.

"Offensively we created many chances through different phases, transitions, our build up play, played good football, defended well, both in high press and low block. We did not concede many high-quality chances, so I'm happy about the performance."

The two teams will face off for the second leg clash on March 4 at the Anoeta Stadium.

Walker has his sights set on claiming 'the biggest prize of all'