Chelsea: Mateo Kovacic tests positive for Covid-19 and misses Champions League visit to Zenit

Mateo Kovacic has tested positive for Covid-19 and will miss Chelsea's Champions League visit to Zenit on Wednesday.

Speaking at his pre-match news conference ahead of the game in St Petersburg, head coach Thomas Tuchel described the news as a "huge setback" for Chelsea.

Croatia midfielder Kovacic had returned to Chelsea training on Monday after hamstring trouble, only to return a positive coronavirus test on Tuesday.

The 27-year-old had been out of action since late October and Blues boss Tuchel had hoped to ease him back in this week.

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N'Golo Kante remains sidelined with a knee issue, while Jorginho has been forced to play through the pain of a back niggle and will also now miss Wednesday night's game.

"We have bad news because Mateo was in training yesterday and with a big smile and it was a pure pleasure to have him back," said Tuchel.

"But he tested positive today, for coronavirus, so he's quarantining for a few days. So it's a huge setback for him personally and for all of us."

Asked if the resurgence of coronavirus has caused extra concerns at Chelsea generally, Tuchel added: "Yes, I was aware that this can happen, me personally.

"I'm not happy not only as a manager but also as a person. But this is the reality at the moment, we have to face it to be ready to adapt and to do the best thing possible to avoid transmission."

Tuchel has built 'a well-oiled machine'

Zenit boss Sergei Semak has heaped praise on Thomas Tuchel's "well-oiled" Chelsea system.

Chelsea play Zenit in St Petersburg on Wednesday, where the Blues can seal top spot in Champions League Group H. If the Blues equal or better Juventus' result against Malmo they will secure first place and a potentially more favourable last-16 draw.

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Chelsea edged past Zenit 1-0 at Stamford Bridge in September, but Semak knows the quality of craftsmanship that manager Tuchel has put into refining his tactical set-up.

"You're talking about individual players but I would like to point out the importance of the system in general, they are like a German machine, well-oiled," said Semak.

"Every person on the pitch knows what to do and how to do it.

"So I would like to refrain from talking about individual qualities, and concentrate more on Chelsea as a team."

Tuchel bemoans 'big mistakes'

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Thomas Tuchel was left to rue a catalogue of "big mistakes" after Chelsea slumped to their second Premier League defeat of the season at West Ham.

The Premier League leaders travelled across the capital knowing victory at the London Stadium would move them four points clear of title rivals Manchester City and Liverpool before they even had the chance to kick a ball this weekend.

But Chelsea paid the price for an error-strewn performance as goalkeeper Edouard Mendy was at fault for two of West Ham's three goals, including Arthur Masuaku's freakish winner.

"I didn't see our performance dip against Manchester United or today, it was enough to win the game," Tuchel said.

"We gave easy goals away, this is unusual - big mistakes that lead to big chances and easy goals. We've done this against United, Watford, and today.

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"We are not good enough in the details at the moment. This is a game about details, I can only repeat myself. Without doing big mistakes, there's a big chance we win this game.

"The [title] race is not interesting at the moment, what is interesting is the next 90 minutes. We have to have the focus right, the attitude right, and to take care of the details because we are not good enough with the details at the moment.

"If you want to protect yourself against counter-attacks, it is impossible to do these kind of mistakes. We have done these three times in a row; this is simply too much."

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