Filip Jorgensen's howler saw Chelsea drop points from a winning position again as Aston Villa secured a comeback 2-1 Premier League victory on Saturday.
The Blues started the game brightly, despite losing Trevoh Chalobah to injury early on, and took the lead in the ninth minute through Enzo Fernandez after excellent wing play from Pedro Neto.
The Argentine could have had a quickfire hat-trick as he headed just wide from a dangerous Cole Palmer cross and then curled one onto the roof of the net.
At the other end, Jorgensen spread himself well to keep out Ollie Watkins' strike, and then Marc Cucurella was at full stretch to deny the England striker soon after.
Villa were slowly gaining the upper hand as the contest wore on, despite Palmer's shot agonisingly hitting the side netting.
Their hard work was undone, however, when Manchester United loanee Marcus Rashford set up Marco Asensio to draw the hosts level in the 59th minute following a lengthy VAR review.
Neto and Palmer then spurned good opportunities after the hour mark as the match became increasingly stretched.
Unai Emery's men looked the more likely to grab a winner and sure enough in the 90th minute, Paris Saint-Germain loanee Asensio's shot squirmed under Jorgensen to give his team all three points.
The result meant Chelsea have won just two of their last nine Premier League games, with the Blues - who have dropped 15 points from winning positions this season - staying sixth and Villa climbing to seventh in the table.
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