Chelsea’s attack has picked the worst time to falter.

Defensive fragility and disciplinary problems have been common threads throughout this campaign but, until now, the attacking talent at Chelsea’s disposal had allowed them to keep putting points on the board in spite of that.

Their goal difference of +15 could yet prove crucial in the race against Manchester United (+13), Liverpool (+8), and Aston Villa (+5) in the race to secure Champions League football next season.

It is fortunate that Chelsea bolstered their goal difference earlier in the campaign, because now the goals have dried up. They have failed to score in three consecutive games in all competitions.

Previously, they had only been shut out three times this season, in goalless Premier League draws against Crystal Palace in August and Bournemouth in December and a 1-0 defeat to Arsenal in the Carabao Cup in February.

Only a couple of weeks ago, they produced one of their most convincing scorelines of the season with a 4-1 win at Aston Villa. So what has changed in such a short time?

Estevao returned from injury as a substitute against Everton last weekend (Alex Livesey/Getty Images)

Chelsea are still creating chances — in fact, their average of 15.3 shots per match across their past four games surpasses their average across the season. First and most obviously, their finishing has taken a turn for the worse. In the first 25 matches of the Premier League season, Chelsea had 3.0 Opta-defined big chances per 90 minutes and converted 1.48 of them, a conversion rate of 49 per cent. In the last six games, they have had 3.3 big chances per 90 but converted just 1.0 of them, or 30 per cent.

That evidently needs to improve — but it is not the full story. Closer examination reveals how specific problems in build-up are slowing them down in the final third.

Revisiting their performance against Villa shows much of what they are now missing. Take Cole Palmer’s goal, Chelsea’s third. After Moises Caicedo’s interception in the Chelsea half, they immediately spot the chance to catch Villa on the transition and Palmer and Alejandro Garnacho begin their runs either side of Joao Pedro.

However, Villa still have a numerical advantage — it is Reece James’ enterprising run, underlapping Palmer on the right, that distracts the defence from his attacking team-mates and creates a crossing opportunity. The Villa defence forgets about Palmer on the edge of the box, who is free to fire home a rebound.

Quick off-ball movement in the wide areas was crucial to Joao Pedro’s equaliser in that match, too. As Fernandez initially looks forward in the midfield, the striker has three Villa defenders blocking him off.

The runs of Jorrel Hato and Malo Gusto pull apart Villa where they have tried to deny Joao Pedro space, distracting them enough for him to dart into the space between the central defenders and finish.

That movement in wide areas has been crucial in Chelsea’s ability to transition into attack quickly. In the past few games, they have lacked either the energy or not made the effort to create those chances.

This example from last weekend’s 3-0 defeat to Everton shows how their transitions have become sluggish. After Pedro Neto carries the ball out of Chelsea’s box and looks to kickstart a counter-attack, he tees up Enzo Fernandez for what could have been a through pass to Palmer or Joao Pedro. Those line-breaking passes are key to Chelsea’s ability to be vertical and sharp in attack. Instead, he lays it sideways to Marc Cucurella — and slightly behind him, which further slows down the attack.

Chelsea progress down the left but do not take opportunities to play Neto and then Joao Pedro in behind. Everton are able to recover and set up to frustrate their efforts, and Fernandez ends up attempting a curled effort from outside the box that Jordan Pickford saves.

Not pushing bodies forward quickly enough also led to this counter-attack in the 1-0 loss to Newcastle United petering out. As James carries the ball downfield, he glances around multiple times, presumably for support — but ends up taking the shot on himself, which is blocked.

Data also shows that Chelsea are playing less directly of late. Their forward pass and long-ball shares have fallen and they have attempted fewer take-ons than earlier in the season.

That reduced urgency and dynamism also helps explain Joao Pedro’s drop-off. The Brazilian had been in superb form, scoring 10 times in Chelsea’s 11 games ending in the win against Villa. He is now goalless in four — hardly a career-defining dry spell but, given how important he was proving to Chelsea’s output, far from ideal.

While Joao Pedro is capable of dropping and carrying the ball from deeper, he is most effective when crashing the box to receive crosses or lurking on the defensive line to make short, well-timed bursts in behind. His equaliser against Villa or his goals against Burnley and Leeds United are prime examples.

As we see from the touchmap below, his involvement in the penalty box has dropped off in the past two Premier League games.

The fact that Chelsea are being less direct in attack fails to take advantage of the striker’s abilities running in behind, and also means opponents have longer to organise defensively and deny him space — partly explaining his reduced involvement. Joao Pedro is also easily tempted to drop back to receive the ball. That can help Chelsea retain possession by giving them an extra option in midfield, but it also removes any kind of target up top.

Fatigue might well have something to do with the reduced directness. Liam Rosenior’s squad will play their 50th game of the season against Port Vale on April 4, and that follows a busy summer at the Club World Cup. Injury problems also mean Rosenior has less ability to rest certain players: Estevao has only just returned from a hamstring injury, while Jamie Gittens, Trevoh Chalobah and Reece James are all sidelined.

Rosenior has had less scope to refresh the attack — particularly while Estevao was out — when those on the pitch are struggling to take their chances.

Chelsea have not stopped creating, but they have eased off the pedal when it comes to the speed of their attacks and that is harming their output.

The opportunity for several squad members to rest — and, as Rosenior said after Everton, for all to ‘reset’ during the international break — is important if Chelsea are to restore some urgency and dynamism to their attack for the final weeks of the season.