The Hammers had looked like enhancing their European hopes and denting Manchester United's bid for Champions League football when makeshift defender Cheikhou Kouyate twice juggled the ball before, with his third touch, hitting a superb volley on the turn into the net.
Radamel Falcao missed a glorious opportunity to equalise 14 minutes from time, but Blind popped up to score late on and earn a 1-1 draw for the visitors, who finished the game with 10 men as Luke Shaw was sent off for two bookable offences.
Wayne Rooney, Falcao, Angel di Maria, Adnan Januzaj and Robin van Persie all started for Manchester United against an injury-depleted West Ham, who deployed midfielder Kouyate in central defence.
The fact goalkeeper David de Gea was the away team's best player after 30 minutes, saving twice from Enner Valencia, told how Louis van Gaal's expensively assembled side struggled to assert themselves.
Kouyate's deflected strike, after Rooney's poor header, sparked United into life, but they had not won away from home after conceding first since December 2013, and not at all under Van Gaal.
But they avoided following Liverpool and Manchester City in leaving Upton Park defeated this term as Blind swept the ball into the net when Carl Jenkinson, on his 23rd birthday, failed to clear Marcos Rojo's lofted ball into the box.
It was harsh on West Ham but extended Manchester United's unbeaten away run in the Premier League to seven games.
Source : PA
Source: PA