It looked as if they were left to count the price of a poor run of form in Europe and were headed for defeat for the third time in four games when Rasmus Hjolund gave Napoli the lead late in the first half.
Needing a win to avoid the February play-off round, the Blues gambled with a trio of Reece James and Mark Cucurella in unfamiliar central defensive roles, a departure from the norm aimed at countering the system favored by their opponents, and the move showed early promise.
Chelsea looked safe with an early lead given by Enzo Fernandez’s penalty when suddenly they were stunned by 23-year-old academy graduate Antonio Vergara, whose first goal in his sixth senior start will not soon be forgotten at City.
Cole Palmer – reportedly set to end his two-and-a-half-year stay in west London and return to Manchester – was on the bench after missing the win at Crystal Palace, and after the Napoli goal Chelsea had no one who looked capable of taking control of the ball and making something of it.
Hjolund gave the hosts the lead and at that point the task seemed too big for Chelsea, who went on to lose.
Then Pedro suddenly turned things around, first scoring with a superb drive from range and then evading the defense in the 82nd minute to seal the win.
Before all this, Chelsea had made a good start. After 17 minutes, James’ free kick was taken into the wall by Juan Jesus, jumping to block it.
Faced with the noise of the hostile home fans, Fernandez remained calm and confidently fired the penalty into the bottom corner.
This was a sign of continued pressure from Napoli that would turn the game.
Giovanni Di Lorenzo scored behind the Chelsea defense and drew a save from Robert Sanchez at his near post, and Napoli easily opened up space on either side of the three central defenders, targeting the wings.
The equalizer largely reflected his increasing control. A failed clearance from Andre Santos in the right-back position went nowhere but straight into Napoli’s possession in midfield.
Mathias Oliveira nodded the ball to Vergara, who headed into the box and then Wesley Fofana headed the ball across goal with ballistic balance and beat Sanchez via post.
More wide open spaces appeared inside the penalty area for Oliveira to exploit, slipping on the ball with a bag of room to pick out Hjolund, who got in front of Fofana and scored with a first-time finish.
Blues boss Liam Rosenior sent Palmer on at the break for some creative energy but it was Pedro who found a moment of genius to level things up. His strike from 25 yards into the top corner was his best since joining Chelsea and was potentially valuable.
Now it was Chelsea’s turn to dominate and check the goal that would hand them command of their European destiny.
It duly arrived, with Pedro making himself a blues hero for dispatching them.
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