Roma and Villarreal booked Europa League semi-final ties against Manchester United and Arsenal respectively.

First-half strikes from Paco Alcacer and Gerard Moreno guided Villarreal through with a 2-1 victory over quarter-final opponents Dinamo Zagreb on Thursday and a 3-1 aggregate triumph.

Villarreal dominated the game and almost took the lead after 25 minutes when forward Samuel Chukwueze rattled the post with a close-range volley.

They did not have to wait long to open the scoring, however, with Alcacer netting 10 minutes later. Chukwueze was initially flagged offside in the build-up, but the goal was allowed to stand following a VAR check.

Moreno doubled the hosts' lead three minutes before the break after Alcacer's effort had been parried by Dominik Livakovic in the Dinamo goal following a marauding run from centre back Raul Albiol to tee up the chance.

Unai Emery was Arsene Wenger's immediate successor at Arsenal

The visitors rallied after the break and Geronimo Rulli was forced into a couple of smart stops in the Villarreal goal while at the other end Chukwueze and Moreno spurned chances to ensure victory.

Mislav Orsic pulled one back for Zagreb 15 minutes from time, but far from setting up a nervy finale the visitors never threatened to get back into the tie as the Spaniards held firm.

"This club with the short history that it has has done so much in La Liga and Europe, which shows just how well it all works here," midfielder Dani Parejo said.

"We've been brilliant in this competition since the group stages. It's just a shame the fans can't be here, as these are the kind of matches you want to play in front of your fans - but this win is for them," he added.

"We took the initiative and controlled things. Yes, they got one back, but we were the better side throughout the tie."

Villarreal will face their coach Unai Emery's former club Arsenal in the last four after the English side overcame Slavia Prague.

AS Roma advanced thanks to a 3-2 aggregate win over Ajax Amsterdam as former Manchester City striker Edin Dzeko's equaliser secured a 1-1 draw in Rome.

Brian Brobbey struck for Ajax four minutes after his halftime introduction but Dzeko’s 72nd minute finish levelled the scores in the quarter-final second leg.

The visitors dominated possession and had a second goal disallowed for a Nicolas Tagliafico foul but struggled to again break down a resolute home defence despite a late onslaught.

Roma will face Manchester United, who defeated Granada with a 4-0 aggregate win, in the last four.