Arsenal, Villarreal, Roma, Man Utd into Europa League semis

London: With their season on the line, Arsenal's players produced a devastating first-half performance Thursday to beat Slavia Prague and reach the Europa League semifinals.

They'll meet a familiar face there.

Arsenal's 4-0 win in the Czech capital -- secured courtesy of a three-goal burst in six minutes from the 18th -- clinched a 5-1 aggregate victory and set up a last-four match against Villarreal, which is managed by Unai Emery.

The Spanish coach spent an underwhelming 18 months at Arsenal as Arsene Wenger's replacement in 2018-19 and is rebuilding his managerial career at Villarreal, which beat Dinamo Zagreb 2-1 and advanced 3-1 on aggregate.

Manchester United and Roma complete the semifinal lineup.

United is back in the last four for a second straight season after beating Spanish team Granada 2-0 for a 4-0 aggregate win.

Roma drew 1-1 with Ajax to squeeze through 3-2 on aggregate.

Arsenal and Roma were under pressure to advance because the Europa League represents their only chance of winning a trophy this season and their only realistic route into next season's Champions League, owing to their lowly current placing in their domestic leagues.

Arsenal is ninth in the Premier League and Roma seventh in Serie A.

The winner of the Europa League earns an automatic spot in the far more lucrative Champions League.

Arsenal sent a message before and during the win over Slavia.

The hosts learned the day before the game that their defender, Ondrej Kudela, had been banned for 10 games for racially abusing Rangers' Glen Kamara during a round-of-16 game last month.

Before kickoff, as Slavia's players stood in a line at the center circle, Arsenal's players took a knee in a symbolic gesture in support of the Black Lives Matter movement, with Alexandre Lacazette doing so right in front of the Slavia team and staring at the players.

Arsenal responded to having an early goal by Emile Smith Rowe ruled out for offside by VAR by scoring three times in quick succession, first though Nicolas Pepe in the 18th and then Lacazette -- from the penalty spot -- and Bukayo Saka.

That meant Slavia, the runaway leader of the Czech league which hadn't lost at home in nearly 18 months, needed to score four goals to qualify. By halftime, the hosts had essentially given up as they removed some of their key players to preserve their condition for the league.