Valencia eased into the semi-finals of the Europa League for the first time in five years with a comfortable 2-0 win at home to fellow Spanish side Villarreal in heavy rain on Thursday for a resounding 5-1 aggregate scoreline.

Valencia's Toni Lato and Dani Parejo scored the goals that secured the victory and set up a meeting with Arsenal and former coach Unai Emery in the last four after the London side won 1-0 at Napoli to wrap up a 3-0 aggregate victory.

Full back Lato strolled into a gaping hole in the visiting defence to volley Valencia in front in the 13th minute at a rain-swept Mestalla to further settle the home side, who enjoyed a 3-1 win at Villarreal in the first leg.

Valencia doubled their lead early in the second half with a free kick by captain Parejo which took a deflection off defender Ramiro Funes Mori, and many fans took the goal as their cue to leave the roofless stadium in search of some shelter.

Meanwhile in Germany, Eintracht Frankfurt beat Benfica 2-0 to overturn a 4-2 first leg deficit and advance to the Europa League last four on the away goal rule for their first European semi-final appearance in 39 years.

Goals from Filip Kostic and Sebastian Rode were enough to put them through and they will next face Chelsea, who beat Slavia Prague.

Eintracht, German Cup winners last season, reached their first semi-final in a European competition since winning the UEFA Cup back in 1980 by punishing their opponents' passive approach.

The Portuguese, finalists in 2013 and 2014, were largely toothless, content to sit back and soak up the pressure but with little to show for up front until after Eintracht's second goal in the 67th minute.