Juergen Klopp's Liverpool held Borussia Dortmund to 1-1 on his return to his former club for the first leg of their Europa League quarterfinal, while two-time defending champion Sevilla and Shakhtar Donetsk won away on Thursday.

Liverpool forward Divock Origi scored against the run of play in the first half, and Dortmund captain Mats Hummels headed in the equalizer just after the break.

Roman Weidenfeller made vital saves to deny Klopp a winning return to the stadium where he spent seven largely successful years.

Klopp - who led Dortmund to back-to-back Bundesliga titles, the German Cup and a Champions League final appearance - was given a warm but reserved welcome.

"I thought the respectful quiet applause was perfect, no singing, no calling," Klopp said. "For the 90 minutes I was completely in the game. Afterward, I was happy that I could hug the lads again."

Sevilla substitute Vicente Iborra struck with seven minutes remaining to put his side in a commanding position with a 2-1 victory at Spanish rival Athletic Bilbao. It was Sevilla's first away win in six European matches.

Shakhtar defeated Braga 2-1 with two goals against the run of play, and Villarreal defeated visiting Sparta Prague 2-1 thanks to a pair from Cedric Bakambu.

Origi stunned the Dortmund fans in the 36th minute after being played through with a header from James Milner. Origi's shot took a slight deflection off Lukasz Piszczek's heel and inside the left post.

Pierre-Emerick Aubameyang and Marco Reus went close as Dortmund sensed an equalizer, but Origi should have scored again before the break when he was denied by Weidenfeller.

Hummels ensured Dortmund stayed unbeaten in 18 competitive games this season when he met Henrikh Mkhitaryan's floated cross with a good header.

But the home side was grateful to Weidenfeller for a string of saves, the first a brilliant low one-handed stop to brilliantly deny Philippe Coutinho.

"I'd rather have made a save less and won the game," the Dortmund 'keeper said.

Dortmund will be the visitor in the return leg next week: "We want to be the first German team to win at Anfield," Hummels said.

Sevilla made the better start in Bilbao with Ever Banega hitting the post and Iago Herrerin saving from Vitolo.

Bilbao recovered and Aritz Aduriz hit the post before Iker Muniain went agonizingly close to breaking the deadlock.

Muniain set up Aduriz to score his competition-leading ninth goal two minutes into the second half, but Timothee Kolodziejczak equalized soon after following a mistake from the Bilbao captain. Muniain's poor header back to his goalkeeper was intercepted by Banega, who set up Kolodziejczak.

Iborra, who went on in the 74th, scored the winner nine minutes later.

In Portugal, Yaroslav Rakitskiy scored after a corner with a volley that hit the ground and took a slight deflection to beat Braga 'keeper Matheus before the break. It was the visitors' first attempt on target.

Facundo Ferreyra put Shakhtar in the driving seat for the second leg with 15 minutes remaining, though Wilson Eduardo scored in the last minute to give Braga some hope.

Bakambu got Villarreal off the mark in the third minute, closing down Sparta goalkeeper David Bicík and deflecting his attempted kick out into the net.

Jakub Brabec equalized with a header from a corner in first-half injury time, but Bakambu picked his spot to restore the home side's deserved lead an hour in.