Confusion and disunity appeared to describe the final days of Unai Emery's 18-month spell as Arsenal boss.

But on Thursday evening, the Villarreal manager and three-time Europa League winner will have the chance to get one over on his former club in a competition that arguably provided one of his darkest moments with the Gunners.

Meanwhile, fellow Spaniard Mikel Arteta, his permanent successor in north London, will be hoping the first leg of the Europa League semi-final acts as a springboard towards more silverware and a strong finish to the campaign.

Having won the FA Cup last term, BBC Sport looks at if Arteta has moved Arsenal on - or whether Europa League specialist Emery can strike again.

"It is strange how things happen. Emery will be looking forward to this - he will say the right things but deep down he will want to beat them badly. Arsenal fans will be nervous," former Tottenham and England winger Chris Waddle told BBC Radio 5 Live.
Arteta 'is not getting the reaction'

Knocked out of both domestic cup competitions by January, the Gunners currently find themselves languishing in 10th in the Premier League and on course for their lowest top-flight finish since 1994-95.

That's two places lower and four points further from a top-four place than when Emery was sacked in November 2019.

"He's in charge now but he's not quite getting the reaction from the team," Keown said about Arteta on BT Sport earlier this month.

"It seems like they're not proactive in games."

But while a string of other ex-Arsenal players and football pundits have also delivered damning assessments,

how does Arteta's record stack up?
Arsenal's Spanish managers
Under Arteta All competitions Under Emery
79 Games 78
40 Wins 43
17 Draws 16
22 Losses 19
127 Goals For 152
80 Goals Against 100
47 Goal difference 52
51% Win percentage 55%

While the Gunners have been more solid in defence under Arteta, it has come at a cost, with the side scoring 25 fewer goals than under his predecessor, despite playing a game more.

Their win percentage has also gone down under Arteta, who signed Willian, Gabriel and Thomas Partey at the end of last summer, plus the January loan arrival of Martin Odegaard from Real Madrid.

Comparisons between the two bosses are not any more favourable based solely on this season, with Arteta's win percentage at 47% and Emery's at 53%.

The Yellow Submarine - the Beatles-inspired nickname for Villareal

- have also scored more goals, conceded fewer and have better possession statistics than the Gunners this term.
Europa offers hope of salvation

Arteta's Arsenal have at least hit form in the Europa League, which appears to represent their best chance of playing in the Champions League next term.

The Gunners, who are the top scorers in the competition, advanced from the group stage with a 100% record and have since knocked out Benfica, Olympiakos and Slavia Prague.

And while the numbers may not bear it out, Emery feels his successor is starting to have an impact.

"Arteta is putting his own stamp on things - in the way they play, it's easy to identify he's bringing back that Arsenal tradition of playing attractive football," said Emery.

"He had his time [playing] there with Arsene Wenger so I'm sure he can apply everything he learned. I think it's a good marriage: Arteta-Arsenal, Arsenal-Arteta.

"When Arsenal are in form, they are a top team. We've seen that this season."
Emery's chance for redemption

Appointed to take over from Wenger, Emery's time at Arsenal began brightly.

A 22-match unbeaten run preceded an appearance in the Europa League final. But a damaging 4-1 defeat by Chelsea was the beginning of the end for the Spaniard, whose time ended amid criticism over his strategy and communication.

However, he now finds himself in the last four of a competition he won three years on the trot with Sevilla.

While Villareal have failed to advance from three semi-finals and also lost a Champions League semi-final to Arsenal, Emery has won his previous four at this stage.

"The club wanted to take a step forward competing in Europe so Emery's record was a massive factor in him being recruited," Spanish football writer Andy West told BBC Sport.

"It would be no surprise at all if they go on and win the tournament. They have never really looked troubled in any tie in the competition so far and Emery has one of the best central defensive pairings in La Liga.

"Raul Albiol is very solid and Pau Torres is a star in the making, while in Spain striker Gerard Moreno they possess probably the best player in La Liga outside Real Madrid and Barcelona.

"He has been involved in nearly every goal Villarreal have scored since January and is probably the best forward in Spain behind [Lionel] Messi and [Karim] Benzema."

BBC Radio 5 Live commentator Ian Dennis, added: "It [the manager match-up] is an interesting headline to build up the tie, but as an Arsenal supporter you are thinking 'oh no- Emery is going to put a spanner in the works'."