There’s a risk of complacency at Chelsea – a smugness caused by too much self-belief and a feeling of entitlement.

That’s the only logical conclusion following two sub-standard performances in four days, culminating in defeat at the London Stadium against a West Ham team who achieved a 3-2 win, despite the Blues being twice ahead and cruising.

In midweek, Chelsea scraped an undeserved 2-1 victory at Watford, so the results probably balance out.

The Watford win was the Blues’ least convincing performance of 2021, caused in part by the lack of experience in midfield.

With Ruben Loftus-Cheek paired with Saul, instead of the absent Jorginho, N’Golo Kante and Mateo Kovacic, it was always going to be different.

But Chelsea were guilty of woeful possession, and there were more turnovers than in an apple pie factory.

It was a fragmented game. A supporter in the stand suffered a heart attack, so there was a long medical delay while he was treated. That meant a 90-minute game finally ended two and a half hours after kick-off. Chelsea rode their luck, and a 73rd-minute winner clinched the points in a 2-1 win.

Drama in the stands at Watford where, to the right of the yellow seats, a fan had a medical emergency

At the London Stadium on Saturday lunchtime, however, the Blues were set for a routine, run-of-the-mill win after Thiago Silva’s 28th-minute header put the visitors ahead.

Then Edouard Mendy tried to be too clever and dribble his way out of his own area under challenge from Jarrod Bowen, and merely upended the West Ham forward. Manuel Lanzini converted the penalty.

Just before the break, the Blues again went ahead with a superb diagonal pass from Hakim Ziyech finding Mason Mount unmarked on the right. His volley will be a goal of the month contender.

Then, in the second half, another defensive blunder by Chelsea allowed Bowen to fire another equaliser in, through Andreas Christensen’s legs.

The Irons, galvanised into believing they could go one better, then had the gall to score with what appeared to be a miskicked cross by sub Arthur Masuaku for a famous 3-2 win that should never have happened.

Chelsea’s players will be given a rocket by Thomas Tuchel, who cannot allow such complacency and lack of focus to take hold. This could be the result which ultimately costs the Blues a title that was surely within their grasp.