Atletico Madrid appear clear underdogs as they welcome European and world champions Liverpool to the Wanda Metropolitano this week.

Liverpool have reached consecutive Champions League finals, winning the decider at Atleti's home last season, and are on course for a stunning record-breaking first Premier League triumph.

Diego Simeone's Atleti have similarly been counted among Europe's elite in years past, winning LaLiga in 2013-14 as they lost the Champions League final, a continental feat that was repeated two years later.

But the Spanish side are facing a battle just to finish in the top four in their domestic league this season.

They face Liverpool in the Champions League last 16, hosting the first leg on Tuesday, and we use Opta data to assess just where they have fallen away ahead of this mammoth task.

Steadily slowing since 2014

Simeone has long had a reputation for setting up his side to stifle the best in Spain and across Europe, but in 2013-14 – the greatest season in their modern history – Atleti packed a punch in attack.

The LaLiga champions scored 116 goals in their 61 matches in all competitions – 1.9 per game.

As they returned to the Champions League final in 2015-16, Atleti netted 89 times in 57 matches (1.6 per game), while they average just 1.1 per game this term.

Diego Costa alone scored 35 in 2013-14, and Atleti clearly lack a similarly prolific marksman right now, but their style of play in attack has also changed considerably.

Atleti still have a similar portion of possession – 46.8 per cent in 2013-14 to 47.5 per cent this campaign – yet they were previously far more effective at launching attacks from their low block.

A total of 108 fast breaks across their 61 matches in their best season works out at 1.8 per game. That was down to 0.4 fast breaks per game in 2015-16, and 0.5 per game in 2019-20.

Atleti have simply become far slower and therefore easier to defend against.

Alvaro Morata no marksman

Atleti's issues would still not be quite so grave if they were taking chances with the same regularity as previously, but a study of Expected Goals (xG) provides cause for concern.

Costa could have been expected to score 31.85 times across the 2013-14 season but instead beat that xG figure with his tally of 35.

The ability of Simeone's side to compete again two years later was largely due to the talents of Antoine Griezmann, meanwhile, signed after the LaLiga title success.

The France striker outperformed his xG of 18.84 by some distance with a total of 24 goals in all competitions, taking several chances he would not have been expected to score from.

This season, Alvaro Morata is Atleti's top scorer with just eight. Worryingly, he would have been expected to score 12.85 times already.

Joao Felix (three goals, 5.87 xG), Costa (two goals, 2.92 xG) and Vitolo (no goals, 1.62 xG) have all toiled in the final third, too, explaining Atleti's poor goals return.

Defensive standards slipping

And Atleti's problems are not just at one end of the field. Jan Oblak remains one of Europe's finest goalkeepers, but even he cannot match previous standards behind a much-changed defence.

The Slovenia star was outstanding in 2015-16, conceding just 26 times across 51 matches, keeping 32 clean sheets and saving 82.67 per cent of shots faced on target.

This term, Oblak has already let in 22 goals in just 31 games, with his save percentage 76.84

Where Atleti could have expected to concede 45.31 goals four seasons ago and allowed just 31, the margins have slimmed considerably: 27.5 xG conceded versus 24 conceded in 2019-20.

Just as Atleti have not effectively replaced Griezmann in attack, they look to be feeling the losses of Diego Godin, Lucas Hernandez and Filipe Luis in defence, with Oblak unable to stem the tide.

Liverpool's all-star attack can now fancy their chances against a previously stingy back line.