Zian Flemming headed the Clarets ahead before a Callum Wilson equaliser just before the half-time whistle.
Despite controlling the majority of the second half, goals from Tomas Soucek and Kyle Walker-Peters condemned the Clarets to defeat despite a late consolation goal from former Hammer Josh Cullen.
Our photographer Kelvin Lister-Stuttard was on hand to capture the emotions of the afternoon.
Can you spot yourself in our gallery of fan pictures?
Burnley fans inside the London Stadium for the Premier League fixture against West Ham United. Photo: Kelvin Lister-Stuttard
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Burnley fans inside the London Stadium for the Premier League fixture against West Ham United. Photo: Kelvin Lister-Stuttard Photo: Kelvin Lister-Stuttard
Burnley fans inside the London Stadium for the Premier League fixture against West Ham United. Photo: Kelvin Lister-Stuttard
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Burnley fans inside the London Stadium for the Premier League fixture against West Ham United. Photo: Kelvin Lister-Stuttard Photo: Kelvin Lister-Stuttard
Burnley fans inside the London Stadium for the Premier League fixture against West Ham United. Photo: Kelvin Lister-Stuttard
3. 3
Burnley fans inside the London Stadium for the Premier League fixture against West Ham United. Photo: Kelvin Lister-Stuttard Photo: Kelvin Lister-Stuttard
Burnley fans inside the London Stadium for the Premier League fixture against West Ham United. Photo: Kelvin Lister-Stuttard
4. 4
Burnley fans inside the London Stadium for the Premier League fixture against West Ham United. Photo: Kelvin Lister-Stuttard Photo: Kelvin Lister-Stuttard