Skip to content
Exclusive

Thomas Tuchel on Expected Goals, unexpected goals and how to stop individual errors costing Chelsea

"It's very untypical for any team who fights for top three to do these kind of mistakes." Thomas Tuchel talks to Sky Sports about searching for answers to Chelsea's sudden defensive fragility. Watch Chelsea vs West Ham live on Sky Sports Premier League from 1pm on Sunday; kick-off 2pm.

Chelsea boss Thomas Tuchel
Image: Chelsea boss Thomas Tuchel discusses how data is helping him analyse uncharacteristic mistakes from his side

Two days on from Chelsea's bizarre beating at the hands of London rivals Arsenal, Thomas Tuchel is still struggling to account for the uncharacteristic errors made by his usually watertight team.

Arsenal hadn't scored in three games but hit four at Stamford Bridge, with Andreas Christensen and the usually reliable Cesar Azpilicueta among the Blues giving Mikel Arteta's men a helping hand.

"It was very strange to analyse," he tells Sky Sports at Chelsea's Cobham training base. "The mix of individual mistakes and then suddenly very good pictures of, for example, counter-pressing and high pressing and ball recoveries in the opponent's half.

"We had so many good pictures. We had the feeling we did many things right. Everything was fine. And then we concede a very strange goal, doing many mistakes in the build up to the goal.

"Especially when it comes from the experienced players who are not normally involved in this and are not typically involved it.

"I don't have an answer right now [for the individual mistakes]. The decisions we take are the right decisions, it's about the executions. But they're not so technically demanding that we think, 'well that was maybe a bit too much'. It's about speed, hitting the ball, over-hitting, under-hitting, a bit of slapstick in one-on-one, funny bounces… strange.

Please use Chrome browser for a more accessible video player

FREE TO WATCH: Highlights from Arsenal’s win against Chelsea in the Premier League.

"Suddenly you try to see a pattern over the last home matches but maybe it's not. Maybe it was a kind of freak result. It feels like a pattern because we had the Real Madrid and Brentford games."

Also See:

That trio of back-to-back home defeats contribute to the fact Chelsea, who had kept six clean sheets in nine games prior to the March international break, have since let in 13 goals in six matches.

It's an alarming drop off which has led to honest meetings between coaches and players.

A stern telling off after the Brentford and Real Madrid results sparked a brief rejuvenation, which saw Chelsea win 6-0 at Southampton, almost come up with a huge comeback at the Bernabeu, and then reach the FA Cup final with a win over Crystal Palace at Wembley.

Tuchel will be hoping the post-match meeting from the Arsenal defeat can have the same impact.

"We've conceded 11 goals in three home matches, we can't pretend everything gets solved by itself," said Tuchel.

"We have to talk about it. It's not like pointing fingers and shouting and being angry all the time, it's just being honest. The players get their feedback - they also get their feedback when they do good -and at some point we need to give them our point of view to be on the same page and be clear where we need to improve."

Tuchel's analysis also includes a deep dive into the data. Before we sat down, he'd referenced the team's Expected Goals (xG) figures and the stats recording their number of errors leading to goals in his press conference, unprompted.

Interestingly, his xG comments came the day after Ralph Hasenhuttl had used the system to defend Southampton's performance in their defeat at Burnley. What was a niche and widely-mocked metric when it first emerged has now become a go-to tool for Premier League managers.

"We knew about it for a long time and now it is out there in public, which I think is good because it gives you a more realistic view on your performance," said Tuchel, when asked about how xG helps him in his work.

What is Expected Goals?

Expected Goals (xG) measures the quality of a shot based on several variables such as assist type, shot angle and distance from goal, whether it was a headed shot and whether it was defined as a big chance.

Adding up a player or team’s expected goals can give us an indication of how many goals a player or team should have scored on average, given the shots they have taken.

"You can lose games in football by being unlucky and you can win games with luck and the result does very often not reflect what happened on the pitch. So it gives you a clear view: how many chances you allow, how many shots in which quality you allow. It's good to have that figure.

"Like with every number, the more you look into it you find your benchmarks. So we know how over a season or half a season what the level of Expected Goals is if you play in a certain structure and if this is suddenly higher we ask ourselves, 'what's happening within the structure?'

"If we concede double the amount we are tempted to say we're in a very unlucky streak at the moment because obviously the quality that we give away is not enough to concede so much and still we concede. That's hard to take."

Indeed, in Chelsea's Premier League and Champions League games since club football resumed after the March internationals, their xG figure suggests they would normally let in eight goals for the quality of chances they've given up. They've let in 13.

In the Premier League, their goals against column was around nine goals better than it may have been from their first 28 games, according to the xG figures of their opponents. In the last three matches, they're three goals worse off.

Those numbers underline how mistakes at the back are costing Chelsea - although giving away needless goals or opportunities has been a persistent problem for much of the season.

According to Opta, only relegation-threatened Everton and Watford have made more errors leading to goals than Chelsea.

"It's very untypical, in any league, for any team in the top of the table, who fights for top three to do these kind of mistakes," Tuchel said shaking his head.

"We have a game like Man Utd at home for example, where it's 0-0, we come from a good streak of results, we're the dominant team, you feel like it's a matter of time before we score and win this game and finish it off and suddenly it's a big mistake and we're 1-0 behind and it makes things very complicated."

A Jorginho penalty at least rescued a point for Chelsea in that fixture back in November but a week later at the London Stadium, the Italian's bad back-pass for Edouard Mendy led to the goalkeeper giving away a penalty, which helped West Ham set the platform for Arthur Masuaku's unlikely cross-shot winner.

The return fixture - live on Sky Sports - offers an opportunity to make amends but Tuchel, who brought up his 50th Premier League game in charge of Chelsea against Arsenal, is keen to keep perspective on what his team have achieved so far this season.

Live Renault Super Sunday

"We have had some fantastic experiences this season," he said. "We won finals, titles, we were fighting for the Carabao Cup to the final game, now a FA Cup final, we were on a good run in the Champions League and did an almost epic game in the Bernabeu…

"So there are a lot of positive things in there and it feels like it and we need to take care now that we don't add a note to it that overshadows all that.

"We struggled with Corona, and we struggled with long-term injuries and we gave our very best and for me personally I still feel super happy to be here and it's an amazing group of players to work with.

"We have our things to solve and since the international break it's a bit of a rollercoaster which is very surprising because it never was like this, so we need to deal with another feature in our story.

"[The West Ham games is] a chance to get back on track. A very strong opponent again. They will not give in, they will not make life easy for us, so it's a big challenge to overcome this inconsistency at the moment and show personality but also a moment to stick together as a group and stay positive."

Win £1million on Saturday!
Win £1million on Saturday!

Another Saturday, another chance to become a millionaire! Super 6. Play for free, entries by 3pm

Around Sky