West Ham manager David Moyes did not hold back in his criticism of referee Chris Kavanagh after the Hammers' 1-0 defeat to Chelsea.

Thomas Tuchel's team clinched a potentially vital win in the race for a top-four finish against surprise Champions League hopefuls West Ham, with Timo Werner's first top-flight goal since February enough to seal all three points at London Stadium.

It was a game not without controversy, however, as West Ham's hopes of pushing for a late equaliser were dashed when Balbuena saw red in the 81st minute.

While clearing the ball down the line on West Ham's right flank, Balbuena – seemingly inadvertently – caught Ben Chilwell on his follow-through.

Referee Kavanagh initially booked Balbuena but, after consultation with the VAR, went over to assess the incident on the pitchside monitor and subsequently changed his decision to a straight red card – a call which infuriated Moyes.

"I think it's a decision made by somebody who's never played the game," he told Sky Sports. 

"I don't know where Balbuena is meant to plant his foot. If they do make that decision then you look at the one a few minutes later which was the same – this time it was Vladimir Coufal and [Antonio] Rudiger – and it was a very similar challenge but they've never done anything about it.

"I don't know how it's a red card, I don't know where he's supposed to plant his foot, and you would only have to be someone who doesn't know the game, hasn't played it, to not know that he's kicked through the ball.

"I don't think for one minute there's a bit of malice in that, or he's tried to catch him. I thought it was a rubbish decision."

It was the second VAR controversy of the day in the Premier League, after Newcastle United's Callum Wilson had a goal disallowed for handball against Liverpool, albeit Joe Willock then struck minutes later to snatch a last-gasp point at Anfield.

Liverpool's draw means that fourth-placed Chelsea are four points clear of the Reds, who sit sixth, with West Ham in fifth.

Thomas Tuchel is unbeaten in all 10 away matches with Chelsea (W8 D2) and is only the second manager in Premier League history to remain unbeaten in his first 10 away games in all competitions with a club, after Claudio Ranieri with Leicester City in 2015, in the year the Foxes won the title.

The former Paris Saint-Germain boss was delighted with Chelsea's overall display, and that of goalscorer Werner, who squandered a great chance to make sure of the win in the second half, and Tuchel told his compatriot to keep up his form heading into the run-in.

"He needs to keep scoring and catch the moment. He is quite often involved in our goals, even in the last weeks, by winning fouls in the penalty area or with assists like against Man City. But nothing helps more than a decisive goal," Tuchel told reporters.

Tuchel is not wrong, with Werner having been directly involved in 20 goals for Chelsea this season (11 goals, nine assists) – the most of any player for the club in all competitions.

"I am very happy because I felt he was strong from the start," Tuchel continued.

"He was very good with distributing the ball, dropping from the number nine position and keeping the ball, he had good timing with his deep runs behind the line, and was involved in many chances and half-chances."