Athletic Club confirmed their place in the round of 32 as winners of UEFA Europa League Group F with a home victory against ŠK Slovan Bratislava, who were already eliminated prior to matchday five.
Óscar de Marcos put the section leaders in front early on but they were pegged back before half-time by Filip Šebo. For all their second-half dominance, Athletic looked as if they may have to settle for a point until Markel Susaeta clinched a fourth Group F victory for Marcelo Bielsa's side 15 minutes from time.
Unbeaten so far in this season's UEFA Europa League, Athletic started the match on the front foot and took the lead when De Marcos latched onto a loose ball in the penalty area and drilled a low shot beneath Matúš Putnocký.
Slovan have found goals hard to come by in Europe this season and having yet to taste victory they could have been expected to fold, but they did exactly the opposite. Vladimír Weiss's side responded positively with Juraj Halenár's superb 30-metre free-kick coming back off the crossbar before Šebo equalised.
The Slovakian international raced onto Marko Milinković's through ball and took it round the onrushing Gorka Iraizoz before finishing into an empty net to score Slovan's second Group F goal.
Athletic improved after the break with half-time substitute Gaizka Toquero at the heart of much of their incisive attacking play. The hosts dominated possession but failed to break down a resolute Slovan defence until De Marcos delivered a deep cross which was headed back across goal and into the bottom right-hand corner by Susaeta.
The Spanish club finish their group stage campaign on 14 December at Paris Saint-Germain FC while Slovan bow out at home against FC Salzburg.