The stark contrast between Kiko Casilla's statistics before and after Leeds United's Cardiff City horror show and Marcelo Bielsa's thoughts

The Spaniard’s statistics make for grim reading since that fateful December afternoon at Elland Road, when the Bluebirds were 3-0 down and seemingly out, before coming back to draw 3-3.

Before that game, Casilla saved 82.5 per cent of the shots he had faced and made 4.7 saves per goal conceded.

Since that game kicked off, Casilla has a save percentage of 44.8 per cent and is making only 0.76 saves per goal conceded.

Those numbers don’t tell the whole story of course; Leeds were once the meanest defence in the country and are no longer able to make such a boast.

They’re conceding more goals and giving up more chances than they were up until December 10.

Pre-Cardiff horror show, opponents were making 5.8 chances per game, but that number has risen to 6.4 since.

Casilla was facing 2.7 shots per game before and has faced 3.2 shots since.

Leeds attack as a team and they defend as a team and, on occasion, Casilla will be the fall guy for his team-mates’ failings, whether it’s a loss of possession in a dangerous area or poor marking at set-pieces.

The absence of Kalvin Phillips for the last two fixtures, Bielsa’s midfield enforcer who breaks up so many opposition attacks, shackles tricky creative types and uses his ball-playing ability to keep a firm grip on possession, should be taken into consideration.

There is no getting around it, however, that Casilla has also been guilty of three individual errors that have led to goals, having not made any, according to data experts Opta, before Cardiff.

Coming for a cross and punching thin air allowed Lee Tomlin to sidefoot a half volley into the Leeds net and start Cardiff’s comeback in earnest.

Similar happened at Birmingham, when he raced off his line but got nowhere near a free-kick that Jeremy Bela headed home.

And his involvement in the only goal of the game against Wigan Athletic last weekend has come under scrutiny.

But Whites head coach, Marcelo Bielsa, does not believe his goalkeeper is suffering from a lack of confidence, he’s just operating in a difficult set of circumstances.

Leeds win fewer aerial battles per game than 21 of their 23 Championship peers.

They look vulnerable from set-pieces delivered into their area and don’t often win the first header from their own at the other end.

When asked recently if he had a theory for their struggle to capitalise on the vast number of corners they win, midfielder Mateusz Klich responded, with a laugh: “Theory? No. We are small?”

Bielsa does not shy away from his side’s lack of aerial ability.

It is one of the reasons why keeping goal for Leeds United is difficult, says the Argentine.

“We don’t have good defensive aerial play, the exception is Liam [Cooper],” he said, after Casilla failed to catch a deflected corner for the Latics’ winner at Elland Road on Saturday.

“We have good headers but not very good headers, just Liam. In English football you have very good players in aerial play, so we have a problem there.

“[So] it looks like the keeper is the one who has to resolve those situations.”

Another issue for Casilla to resolve is the gulf between himself and his team-mates.

Leeds press high up the pitch, with full-backs who play like second wingers and centre-backs who step up into the play to make interceptions and keep their side on the front foot.

Bielsa says that distance can create moments of doubt.

“Normally the teams we face have a distance between the keeper and their defence of 10 metres,” he said.

“But Leeds play with 40 or 50 metres between the keeper and our defence.

“So to manage the time and the co-ordination to play with a free man, sometimes it creates doubt.

“If you remember the situation [against Wigan] when Ben White and Casilla had to resolve the moment with the centre-forward, it was a lack of co-ordination but, just to make a comparison in minute 95 against Millwall, with five players inside the six-yard box, Casilla took the ball in the box [from a late corner].”

Bielsa refuted the suggestion that the former Real Madrid stopper’s confidence has dipped.

And he points out that statistics that might, on the face of it, suggest otherwise, need to be viewed within their proper context.

“I couldn’t say that he is in a moment with a lack of confidence,” said Bielsa.

“But what I say is that being a keeper in Leeds is difficult.

“If you watch our matches, the opposing keeper has a lot of impact in the match.

“Of course if they have four chances and we concede a goal, then after it looks like the average is low for him.

“Maybe the opponent’s keeper concedes a goal but faces 30 chances so the relationship regarding chances and goals is different.”

Even taking into consideration the difficulty of his job and the context his statistics should sit within, Casilla's form is a problem for Leeds United, just as much as Leeds United’s form is a problem for Casilla. Both must improve.