It isn’t going to be easy. Villarreal may not have had as dazzling a season as Borussia Dortmund, but Liverpool are unlikely to find getting past them any less problematic. This league campaign they’ve lost only twice at home, beaten both Madrid teams, drawn with Barcelona, and been in the top four since the start of December.





But let’s start with the good news. They don’t tend to be dangerous from set-pieces and have scored only one header all season, which means they don’t look well equipped to exploit Liverpool’s biggest defensive weakness. Their league form isn’t great, seeing them earn just one point from their past three games.





Villarreal are a curious team in some ways. Their squad contains four fine forwards in Soldado (right), Bakambu, Adrian Lopez and Baptistao, but the team doesn’t knock in many goals, currently lying 11th in the La Liga scoring charts and with the lowest number of shots in the league. Their passing game can be mesmerising at times, but they don’t seem to have any interest in playing possession football.





They set out in a compact 4-4-2 formation that’s hard to break down, leaving very little of the space between the lines in which the likes of Lallana and Coutinho thrive, and they prefer to play on the counter. Their wide midfielders – likely to be Denis Suarez and Castillejo on Thursday – tend to occupy the half-spaces, rather than hugging the touchlines.





When they win the ball, they try to move it forward as rapidly as possible, often by playing risky vertical passes. When done successfully, the results can be intoxicating, although more often it leads to Villarreal quickly surrendering possession.





This raises some obvious concerns for Liverpool. Deploying James Milner in a midfield two again, as Klopp did to disastrous effect for the first hour of the second leg against Dortmund, would seem to be inviting trouble. Then there’s the question of who will replace Sakho in central defence. Should Klopp opt for Martin Skrtel (left), who has a tendency to retreat towards his own goal when opponents are running at him, then the field may open up dangerously for Villarreal as they mount their trademark counter-attacks.





When Villarreal do lose the ball, they immediately and aggressively press their opponents high up the pitch. If the opposition are able to play around or through this press, it can leave Villarreal vulnerable to counter-attacks themselves. Should they fail to regain possession quickly, they then fall back into a well-drilled low block that's difficult to cut through. They have the third best defence in La Liga, having conceded fewer goals than Real Madrid, and the highest number of defensive actions in the league, as well as the fewest defensive errors leading to a goal. Liverpool will not find it easy to create chances.





One weakness in Villarreal’s play that the stats fail to show up is the difficulty they have defending crosses. Christian Benteke’s return to full training this week may just prove to be timely. If you had to pick out an unlikely Liverpool hero for this tie, it would have to be the much-maligned Belgian.





Villarreal’s good form this season is remarkable given that half their first-team is new. Six summer arrivals – Soldado, Castillejo, Bakambu, Denis Suarez (right), Baptistao and goalkeeper Areola – have already made more than 30 appearances. Soldado is now more of a creator than a finisher, with double the amount of league assists of any other Villarreal player, and seems to developing into a second-striker, rather than the prolific focal point of the attack that he was at Valencia.





Manager Marcelino deserves enormous credit for the way his side survived the departure of all of last season’s top five league goalscorers in the summer. Not only did star striker Luciano Vietto leave to join Atleti, but the club also lost Gerard, loanee Denis Cheryshev, Moises Gomez and Uche.









The side’s stand-out performers this season have been Congolese striker Bakambu, with 22 goals in all competitions (see video above), and Denis Suarez, signed from Barcelona, who have retained a buy-back option, and usually deployed as an inverted winger. It would seem sensible to use Milner on the right of the three in a 4-2-3-1 in order to counter the obvious threat Suarez poses.





No one's yet comparing this Villarreal team to the exceptional Manuel Pellegrini-coached side that reached the semi-final of the Champions League in 2006 and two years later finished runners-up in La Liga. But this season they’ve already proven they can make life difficult for some of the best teams in the world – and this Liverpool squad is a long way from that level. It’s likely to be another nerve-wracking night. That’s the Liverpool way.