Madrid, Feb 19 (IANS): La Liga sides participate in the knock-out round of the Europa League Thursday.

Villarreal should be favourites to qualify for the last 16 of the competition as they entertain Austrian side Salzburg in the first leg of their tie, reports Xinhua.

Villarreal suffered a surprise defeat to Rayo Vallecano at the weekend, a sign that they could suffer without central midfielder and captain Bruno Soriano. But Marcelino Garcia's men are favourites as long as they can keep a close eye on Salzburg's Spanish striker Jonathan Soriano.

The 29-year-old Soriano, a former Barcelona B-team player has consistently found the net for the Austrian outfit and netted a hat-trick against Dynamo Zagreb in the group stage of the competition. He will probably see this as a long-awaited chance to show just what he can do in his homeland.

Athletic Club Bilbao have a difficult task as they play their first leg away to Italian side Torino.

Torino are in a good run of form in Serie-A, while the same cannot be said for Athletic, who are hovering an uncomfortable five points above the relegation zone in the La Liga.

Perhaps with half an eye on his side's vital league game at home to Rayo Vallecano Sunday, Athletic coach Ernesto Valverde has decided to rest star striker, Aritz Aduriz, left back Mikel Balenziaga and winger, Markel Susaeta. That means either Borja Viguera or Kike Sola will lead the attack and Jon Aurtenetxe will play on the left.

Spain's final representative is the reigning Europa League Champion Sevilla, who have a tough tie against German outfit Borussia Munchengladbach.

Sevilla are currently fifth in the La Liga table and while it's probably fair to say their aim for the season is to finish fourth and return to the Champions League, coach Unai Emery can't afford to take this competition lightly.

He will make some concessions to the fixture calendar, however, with Kevin Gameiro leading the attack with Carlos Bacca likely to start the game on the bench.