Mesut Ozil (left) and Jack Wilshere (right) trained on Wednesday

EUROPA LEAGUE

Arsenal’s biggest challenge will be finding the back of the net, because Atletico’s challenge is founded – as it has been throughout the Simeone era, which began in 2011 – on a magnificent defensive record.

After Sunday’s goalless draw with Real Betis, they have now kept a remarkable 11 consecutive clean sheets at home, with Girona forward Portu the last visiting player to score at the gleaming new Estadio Wanda Metropolitano more than three months ago.

That sequence includes victories in previous Europa League knockout ties against FC Copenhagen (1-0), Lokomotiv Moscow (3-0) and Sporting Lisbon (2-0).

However, Atletico haven’t been anywhere near as watertight away from home, failing to keep a clean sheet in their last eight away games and losing three of the last four. But they still boast the best defensive record in La Liga with just 18 goals conceded in 34 games.

So it’s clear that Arsenal need to establish a solid advantage from the first leg, but it won’t be easy for Wenger’s men to find their way past incredibly consistent goalkeeper Oblak, who did nothing to ease speculation over his future by speaking to the media after Sunday’s draw with Betis and stating he doesn’t know where he’ll be playing next season.

The Slovenia international has been heavily linked with a summer move to Paris St-Germain, who are supposedly not put off by his 100m euros (£87m) buyout clause, with Arsenal and Liverpool also reportedly interested in making Oblak the most expensive goalkeeper in the world.

Atletico midfielder Koke has urged his club to give the 25-year-old shot-stopper a “blank cheque” to keep him, but Oblak’s lack of public commitment to his future has left many fans resigned to the prospect of losing a player who been a pillar of strength since signing from Benfica in 2014.

In front of Oblak, the back four is marshalled by the no-nonsense ‘Row Z’-style defending of the fearless Godin, with rising star Lucas Hernandez – brother of Real Madrid defender Theo – deputising for (and perhaps even displacing) injured Luis at left-back, while dynamic Croatia international Sime Vrsaljko competes with Juanfran for the right-back slot.

So the names might be mostly different from the famous Atletico defences of recent years, but thanks to Simeone’s meticulous drilling they are still incredibly difficult to score against. And just to make things even harder, the Argentine boss has said he’s considering using an extra centre-back and employing a five-man defence against Arsenal this evening.

For all the goalscoring exploits of Antoine Griezmann – undoubtedly Atletico’s biggest star – over the last few years, the versatile forward has one massive gap on his CV: he has never won a major trophy.

The 27-year-old Frenchman was part of Real Sociedad’s second-tier promotion-winning team in 2010, and Atletico won the Spanish Super Cup against Real Madrid just after he joined in the summer of 2014, but defeats in the Champions League final and European Championship final in 2016 left him waiting for more significant silverware.

Now, it appears, Griezmann’s patience has run out and he’s decided to boost his chances of taking titles by joining Barcelona, who are very confident of securing his signature by paying his 100m euros (£87m) buyout clause in the summer – even though Simeone has claimed he has not given up hope of persuading him to stay.

Griezmann was close to joining Manchester United for a similar fee last year, but he eventually decided to stick with Atletico as a sign of respect after the club were prevented from recruiting a replacement by a FIFA transfer ban.

Earlier in the season it looked like he was regretting his decision to stay after making a slow start, but he has regained top form since the January arrival of Diego Costa, with the former Chelsea man’s muscular approach helping to create space (and tire out opposition defenders) for Griezmann’s benefit.

However, that almost certainly won’t be the case today because Costa is struggling to recover from a hamstring injury suffered in the quarter-final against Portuguese side Sporting, although Simeone is confident the powerful forward will be back in time for the second leg.

T0DAY (8:05pm)

Arsenal v Atletico

Marseille v Salzburg