The mural was vandalized shortly after England lost the European Championship final to Italy on Sunday - when Rashford was one of the three on the team who missed the decisive penalty kick - but the racist messages scrawled on the painting were quickly covered.
Since then, several hundred supportive messages and flags have been put there.
Rashford himself wrote on Twitter on Tuesday night that he was overwhelmed, grateful and speechless by the support.
The mural was created in November last year to draw attention to Rashford's work against child starvation in the world.