6th April 2016. By Karl Matchett.
The tie of the round in the UEFA Europa League quarter-finals sees Jurgen Klopp's current side take on his old one, with Liverpool travelling to Borussia Dortmund for the first leg on Thursday.

While improvements have clearly been made to the English club's way of playing under Klopp, in both halves of the field, he is still ultimately working with the same players that have been in place and flattered to deceive for the past season and a half; in other words, there's only so much he can do with a better shape and tactical game plan, if the individual errors are still frequently seen.

The biggest issue remains the defence. It is stronger and more consistent than it was last season, or even in the first half of this campaign, but still the problems remain. Mamadou Sakho is the best defender in the squad, but remains prone to the odd half-hour meltdown. It can cost Liverpool two or three chances in succession when he hits one of those spells, and while Dejan Lovren is certainly up there with the biggest transitions since Klopp's arrival, his decision making still leaves a lot to be desired at times.

Add in Simon Mignolet's inconsistencies, the absolute shambles of a return from injury that was Martin Skrtel against Southampton and it's clear that the Reds cannot rely on their defence at this point.

With specific regard to their Europa League tie, there's the opposite aspect to consider: the attackers that the Reds will be facing are among some of Europe's finest this season. BVB have scored 67 in 28 Bundesliga games, outscoring even leaders Bayern Munich. Their strike rate of 2.4 goals per league game is still a little shy of the likes of Real Madrid or Barcelona, but is far better than anybody in the Premier League; Manchester City currently post the best goals per game rate of just 1.8, so Liverpool will be facing a completely different class of offensive quality over the two legs.

Put together a lightning quick, clinical attack with a porous defence and Liverpool obviously have a problem to deal with. The only viable solution, in the absence of a new face to come in at the back, is to make improvements in their own attack.

Roberto Firmino has been excellent since the turn of the year but is struggling for fitness, while none of the strikers have been on the goal trail of late. Daniel Sturridge is back to getting regular game time, but the goals aren't yet flowing. Instead it has been left to Philippe Coutinho to regularly come up with something worthy of being a match-winner; against Manchester United he managed it in outrageous fashion to set up the clash with Dortmund, while Southampton, Spurs and Man City have also found the Brazilian too hot to handle of late.

Coutinho will find himself being central to Klopp's plans of success, not just against Dortmund but for the rest of the season and into next year and the real rebuild, but for any chance of progression in the Europa League, Liverpool desperately need someone else to come up big.

Adam Lallana, Jordan Henderson, James Milner. Each have their own strengths and weaknesses, but goalscoring is too rarely among the positives for each. Emre Can plays the most disciplined role of all the midfielders so can perhaps be excluded, but one of the more offensive-minded central quartet must be more clinical against Dortmund if a chance falls their way.

Of course, should Sturridge reignite his season at a most opportune moment or Divock Origi make good on his recent improvement to add goals as well as movement and link play, the tie becomes rather closer and more intriguing as a 180-minute battle.

But overall it is also a barometer of sorts for Liverpool; if Dortmund, challenging for league and European honours, are at the level the Reds aspire to, it will surely also show the areas of the pitch where Klopp must improve in summer.

The odds are, a world class attack will show up an improved, but still unreliable, mid-table defence and suggest that this is where the biggest need will be at season's end. Having an impact at the other end of the pitch though could still yet see Liverpool spring an improbable surprise and reach the last four of the competition, but it will take a big improvement from the team as a whole attacking unit to match the output of Dortmund over two legs.