Champions League: Oblak and De Gea key battle in Atletico vs Manchester United

Manchester United have not faced Atletico Madrid in European competition since the 1991-92 Cup Winners' Cup last 16, a tie the Spanish side won 4-1 on aggregate as Luis Aragonés got the better of Alex Ferguson.

That was a meeting of two teams on the up: United were a year away from their first of 13 league titles under Ferguson, while Atleti would go on to win consecutive Copas del Rey, with a LaLiga triumph coming in 1996. Twenty years on, Atleti and United meet again in the last 16 of the Champions League, a competition neither is expected to win but one that represents the only means of salvaging their respectively rotten seasons.

It's a difficult one to call. United have become more resolute and less porous under Ralf Rangnick, losing just once over 90 minutes since Ole Gunnar Solskjaer was sacked in late November, but in their 15 games under their interim manager, they have not been tested by elite opposition. Atleti, champions last season, are 15 points off the pace set by Real Madrid in 2021-22 and, in the time Rangnick has been at Old Trafford, they have won six and lost eight of 15 matches in all competitions.

These are well-matched, dispirited teams, who occasionally thrill in attack but always unnerve in defence. Neither looks favourite to win, and neither can afford to lose.

It has, therefore, become a big-pressure situation for the goalkeepers – and that's where form starts to differ wildly.

De Gea returns to Atlético for the first time

This will be David de Gea's first competitive meeting with Atleti since he left for United in 2011. He probably didn't imagine he would win fewer league titles than his old club in the decade to follow, but that's another story.

De Gea can at least step onto the pitch at the Wanda Metropolitano on Wednesday knowing he can claim to be one of the best in the business again based on form – a claim that opposite number Jan Oblak certainly can't make.

We know United have been extremely vulnerable this season. In all competitions, they have faced 465 shots, the fifth-highest tally among teams in Europe's top five leagues; 168 of those attempts have been on target, the third-highest number a team has faced. What is particularly worrying is that 21 of their opponents' shots have come directly from United mistakes, the highest number on the continent behind Sevilla (23).

Looking at expected goals on target – a way of measuring not just the quality of a chance (xG) but the quality of the attempt itself – United's figure against stands at 51.1 in all competitions, the third-worst among Europe's top five leagues. And yet, they have conceded 44 goals – far more than pretenders to trophies should be letting in, but around seven fewer than the numbers suggest they should. Much of that is down to De Gea.

In the Premier League alone, De Gea has made 96 saves from 128 shots on target faced, giving him a save percentage of 73.44. No other keeper has made as many stops and only Leeds United's Illan Meslier has faced more attempts, yet Meslier has conceded 50 goals to De Gea's 34. Using that same xGOT model and subtracting goals conceded (excluding own goals), we can work out a value for how many goals a keeper has prevented through saves. For De Gea, that figure is 7.1, the best in the league.

If you include all competitions, De Gea has faced the most shots on target (157) among top-five-league teams apart from Leicester City's Kasper Schmeichel (158), again showing just how fragile United can be without the ball. Looking at that 'goals prevented' metric again, De Gea is at 7.86 – in other words, he's prevented roughly eight goals through the quality of his shot-stopping. Across the continent, only two keepers to play at least 15 times this season can do better.

Oblak's save percentage plummets in 2021-22

Preventing goals and high save percentages have traditionally been where Oblak thrives. Since his Atleti debut in September 2014, he has the most clean sheets (167) in Europe's top five leagues and a save percentage of 76.5, the third-highest. According to the data, Oblak has prevented just over 51 goals in that time, at least four more than any other keeper and nearly 20 more than De Gea. It makes his form this season all the more troubling.

Oblak has faced 50 fewer shots on target this season than De Gea – implying Atleti's defence is still stronger than United's, even accounting for their dip in standards – yet he has conceded five goals more than the Spain international. Oblak has saved 61, or 57 per cent, of the shots he has faced this season, which is an alarming drop from his career average of 76.52 per cent in Atleti colours.

Using that same 'goals prevented' calculation, Oblak is at -7.05, meaning he has conceded at least seven goals more than should reasonably be expected. Among Europe's top leagues, only seven keepers come off worse this season, and only four by a significant degree.

There is of course more to a keeper's value than the number of times the ball goes in his net, but these numbers give us a good indication of which ones are performing well when it comes to rudimentary shot-stopping. A 15-goal swing between De Gea and Oblak this season tells you everything you need to know about their recent standards, and why Atleti will have more cause for concern than United in this hugely important knockout tie.