For 65 minutes, the Magpies held out against the league leaders but fell apart when Reece James opened the scoring.
Indeed, James scored a brace as a penalty from Jorginho inflicted further relegation fears on Tyneside.
Our writer Jordan Cronin was at St James’s Park – and here’s how he rated each Newcastle player:
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1. Karl Darlow - 4
Endured a nightmare couple of minutes. Was already on the floor when James fired his second before bringing down Havertz for the penalty, scored by Jorginho.
Photo: Naomi Baker
2. Javier Manquillo - 6
Manquillo dealt with a lot of attacks down his side in the first-half. After the break, Chelsea played through the middle.
Photo: Laurence Griffiths
3. Emil Krafth - 5
Handed his second successive start. Provides pace on the right side of the back three but had no positional awarness.
Photo: Justin Setterfield
4. Jamaal Lascelles - 6
United’s captain, the leader in the backline, watched his side collapse in the remaining quarter-hour or so.
Photo: Ian MacNicol