That is the view of Spanish football expert Guillem Balague, the much-respected pundit, author and journalist who also happens to be a fan of the Barcelona-based side.
From a gold and black point of view, it has been difficult to know what to expect from Espanyol as, while they won Group H, they are bottom of the La Liga and already on their third manager of the season, Abelardo, after short stints for both David Gallego and Pablo Machin.
Fortunately, Balague has offered a fascinating insight into Wolves' opponents as he told the Express & Star: "It's been a confusing season.
"We lost our best striker (Borja Iglesias, to Betis) and best centre-back (Mario Hermoso, to Atletico Madrid), and we replaced them with minor versions.
"As a consequence, we've suffered. We got rid of a very good manager (Rubi, also to Betis) and gave a chance to a young one from within (Gallego) – it didn't work.
"Then, another manager came in (Machin) and the players didn't believe in him, so that was another few months wasted.
"Eventually, we got the right manager, and the 40 million euros spent in January has helped. It's the biggest expenditure Espanyol has ever done. That got us three players.
"We bought Adrian Embarba in for 10million, spent 25million on Raul de Tomas who will be missing as he's injured, and bought Leandro Cabrera the centre-back for around nine million.
"The team, now, is a bit more compact. Since the arrival of Abelardo and the 2-2 draw against Barcelona in January, you see a team that does things very simply, doesn't overcomplicate, 4-4-2.
"Gallego was one who built from the back but he wasn't very clear in his message – Espanyol haven't got the players for that anyway.
"Abelardo recognises with a striker like De Tomas, you can have another one next to him, and midfielders who work really hard – defend and attack, but defend mostly.
"That's how he has managed, but De Tomas is missing. He's scored five goals in the five games he has played, so that's a big disadvantage. We are, really, clearly not favourites in this one."
The bookmakers agree with Balague, too. They have all got Wolves down as favourites.
So, how did Espanyol top their group, which also included Ferencvaros, Ludogorets and CSKA Moscow, despite being rock-bottom in the league?
"They've only been good in Europe, to be honest, although never necessarily with the best XI," admitted Balague, the former host of Revista de La Liga on Sky.
"Europe always gives you more, doesn't it? In the league, I haven't seen a very good performance.
"I've seen some hard-working ones. Against Sevilla this past weekend, for instance, the 2-2 draw was as much to do with Sevilla being in a different dynamic.
"Espanyol were solid, had three chances and scored twice, so they were efficient. Usually, it tends to be the other way.
"A lot of things have to happen for Espanyol to match a team like Wolves.
"I'm not saying it's impossible. There have been two or three games, especially in Europe, where things have worked.
"But with De Tomas out, the strikers don't score. The midfielders don't score either, and there's not much on the bench.
"It really is a difficult season and the target is not to be relegated as that would mean 80million euros lost.
"But, of course, this is a competition everybody looks forward to being part of."
After finishing seventh last season, being relegated to the Spanish second tier would be nothing short of a catastrophe for Espanyol.
And because of that, Balague feels there will probably be a few changes to the team on Thursday.
Espanyol face 15th-placed Real Valladolid on Sunday in the league, so will have that important match firmly in their minds.
"I think it will be a strong team. But there is a game on Sunday against Valladolid and if Espanyol beat them, it involves Valladolid in the relegation battle," said Balague.
"That is the big game, so if there are any doubts over a player being able to play two full games, they'll be rested in Europe.
"But, the players who are not regulars have done really well – Oscar Melendo, Victor Gomez.
"Youngsters may get the opportunity, but the Europa League is taken very seriously in Spain, so it will not be a complete change of 11 players.
"But, they will have an eye on Sunday's game, I'm sure."
Espanyol, although this term has been tricky, to say the least, do have a strong history in the Europa League – or the Uefa Cup as it used to be known.
They made it to the final in 1988 and 2007 – and Balague is proud to see them back in the knockout stages of the competition.
He will be at Molineux, and the RCDE Stadium for the return leg, as a fan.
When asked how it will go, Balague added: "A goal away would be very good for Espanyol, against a prestigious rival. The stadium will be almost full for the return leg.
"I get the impression that Nuno Espirito Santo's thinking is that nothing is decided in the first game, in the way of Jose Mourinho.
"So, even a goalless draw, would be a good result, and everything is to be decided then.
"I'm just fascinated to see how Wolves set up, and if they decide to dominate the game as Espanyol haven't got the ability to do that.
"If that's the case, counter-attacking will be the thing for Espanyol – but we haven't got very fast players either.
"I'll be there as it's good to go to a place like Wolves. I followed the run to the Uefa Cup final in 1988, and I haven't been to watch Espanyol in European competition since because of being here in England. So, I'm going to enjoy both legs – as a fan."