First-half goals from Crysencio Summerville and Valentin Castellanos saw the Clarets slump to a 2-0 defeat on home turf to their fellow strugglers.
But the main talking point came in the stands, as frustrations boiled over among the Clarets faithful who voiced their discontent with Parker.
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Chants of “getting sacked in the morning” and “we want Parker out” were heard on more than one occasion as Burnley failed to win for the 16th straight league game.
Here’s how the Clarets rated:
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5. Lucas Pires - 5/10
Endured a really difficult first half, struggling with the wet conditions. It was his error that led to West Ham's opener Photo: Kelvin Lister-Stuttard Photo: Kelvin Lister-Stuttard
6. Florentino Luis - 5/10
Hooked off at half time on a booking, having been carded for a cynical foul on Crysencio Summerville as Parker reverted to a back five Photo: Kelvin Lister-Stuttard Photo: Kelvin Lister-Stuttard
7. Lesley Ugochukwu - 5/10
Got to use his height and strength to better effect and on a more consistent basis. Drifts in and out of games too often. (Photo by Kate McShane/Getty Images) Photo: Kate McShane
8. Hannibal - 5/10
Provided a dangerous low ball across the box for Jaidon Anthony's chance as he played in a slightly more advanced role, but otherwise didn't make much of an impact Photo: Kelvin Lister-Stuttard Photo: Kelvin Lister-Stuttard