Chelsea's recent fruitful passage was ended for the time being after Ellis Simms stepped up to the plate and provided Everton with a late hero, restoring parity in the dying embers of the Premier League clash at Stamford Bridge.

Sean Dyche's Toffees were dogged and resilient in their defensive approach, keeping the home side at bay until after the break, when Joao Felix, who had been energetic in the first half, thumped in a driven strike past the hapless Toffees shot-stopper Jordan Pickford.

Everton restored parity after Abdoulaye Doucoure found the back of the home net as Stamford Bridge approached the final 20 minutes of the affair, before Kai Havertz coolly converted from the penalty spot - scoring for a third successive match - and secured what appeared to be a fourth consecutive victory for Graham Potter's Blues.

Positivity dissipated when substitute striker Simms stole the limelight right before the death; Everton's utility striker - recalled from EFL Championship outfit Sunderland in January - bypassed the west London team's defence and scored his first Toffees goal after bullying centre-back Kalidou Koulibaly and silencing the home faithful.

Was Koulibaly at fault vs Everton?

Since signing for Chelsea for £33m in the summer, part of an affluent £600m overhaul under Todd Boehly's ownership this season, Koulibaly has been a regular presence, though the colossus has not quite had the emphatic effect that was anticipated.

Making 26 appearances across all competitions, the 31-year-old has been branded "anxious" and "nervy" by Premier League legend Ian Wright, and now looks to have regressed after offering a discernible improvement over the past few weeks.

As per Sofascore, the Senegalese titan's error against the Merseysiders was evidenced in his lowly match rating of 6.4, better only than Kepa Arrizabalaga's in the Blues starting line-up, with the £72m Spanish shot-stopper making just one save all evening, indeed shipping in two goals and being chastised for "weak goalkeeping" by journalist Josh Bunting.

Taking 63 touches, Koulibaly picked up a yellow card and completed 85% of his passes, winning just two duels all evening and indeed being skinned by Simms in the final minutes, with Hogan Ephraim proclaiming him to have been "man handled" by the 22-year-old forward.

Journalist Patrick Boyland also remarked that Koulibaly had been left "on toast" by Simms, halting Chelsea's revival and keeping the outfit 11 points behind fourth-placed London rivals Tottenham Hotspur.

Things are starting to come together at Stamford Bridge, but Dyche's team issued a timely reminder that there is plenty of work still to be done in order to reach the desired level, and Koulibaly must improve if he wants to continue to play a part in the resurgence.