Goals in either half from Fernando Llorente and Mikel San Jose earned Athletic a 2-0 win at Austria Vienna, taking them into the last 32 alongside Group L leaders Werder Bremen, who beat Portuguese side Nacional 4-1.
The Belgian club drew 0-0 at already-qualified defending champions Shakhtar Donetsk and will host Toulouse in a winner-takes-all final group match.
FC Copenhagen moved level on seven points with Sparta by beating CFR Cluj 2-0, thereby eliminating the Romanians from the competition, and the Danish side will go through if they avoid defeat at home to Sparta in their last game.
Groups D, E and F were in action later on Thursday, with Sporting Lisbon looking for the point they need to qualify from Group D at home to Heerenveen and Serie A giants Roma looking to leapfrog Swiss side Basel at the top of Group E.
The top two teams from each of the 12 groups go through to the round of 32, where they will be joined by the third-placed teams from the Champions League group phase, which include five-time European champions Liverpool.
Source: AFP Global Edition