It looked as if Senegal midfielder Cheikhou Kouyate, deployed as an auxiliary centre-back by Hammers manager Sam Allardyce, had won the game for the home side with a brilliant close-range finish in the 49th minute after he controlled Mark Noble’s free kick with his back to goal.
But Blind struck from the edge of the area in the second minute of stoppage-time after Marcus Rojo’s ball into the box was only partly cleared.
There was still time for United left-back Luke Shaw to be sent off for a lunge on Stewart Downing and the result prevented Louis van Gaal’s side from leapfrogging Southampton into third place.
“We played very badly in the first half and showed a lot of spirit in the second half,” United manager van Gaal told Sky Sports.
“We gave away that goal and then played football but you have to do it from the first minute.
“But what spirit after the goal and I thanked my players for that,” added the Dutchman after seeing compatriot Blind spare United’s blushes.
Allradyce, meanwhile, was left ruing what might have been.
“A win would have been nothing more than we deserved,” he told the BBC.
“It’s a great shame we conceded the goal but a fantastic performance which entertained the crowd — I always respect the point against one of the ‘big boys’ even though they got the goal late.”
Earlier, Peter Crouch’s late equaliser ensured Stoke City gained a 1-1 draw away to Newcastle that kept them in 10th place.
A mediocre match burst into life in the final 16 minutes when Jack Colback, who moments earlier might have been sent off for a second bookable offence following a poor challenge on Victor Moses, fired Newcastle into the lead to the delight of the St James’ Park faithful.
But much-travelled former England striker Crouch made sure Newcastle did not leapfrog Stoke when the beanpole forward’s trademark header at the back post gave the visitors a share of the spoils.
“I was pleased to get the goal and the point was the least we deserved,” Crouch said.
Meanwhile, midfielder Colback admitted he had been fortunate to be on the pitch when he scored.
“I made two fouls all game so I wasn’t repeat-offending but if I had of been sent off I wouldn’t have had much argument,” he said.
– Burnley blow another lead –
Sunday’s first of three Premier League fixtures saw Burnley let slip a two-goal advantage for the third straight match as they were held to a 2-2 draw by fellow-strugglers West Bromwich Albion at Turf Moor.
This result did see the Clarets climb out of the bottom three, although they are now just a point clear of the relegation zone.
Burnley were 2-0 in front after just over half an hour thanks to Ashley Barnes and Danny Ings.
But they conceded two headed goals from corners, Chris Brunt pulling one back for the Baggies on the stroke of half-time before Nigeria striker Brown Ideye equalised in the 67th minute.
Ideye’s leveller was the 14th headed goal that Burnley had conceded in the league this season — the most in the English top-flight.
Burnley at least came away with a draw, having lost 3-2 to Crystal Palace after going 2-0 up in their last home match and then going out of the FA Cup with a 4-2 defeat by Tottenham Hotspur after establishing a two-goal lead at White Hart Lane.
“It’s just a lack of concentration from set-pieces that we need to improve on,” said Ings. “It’s very disappointing from ourselves today, considering we started the game so well.”
Relieved West Brom boss Tony Pulis said: “We started as though it was a Sunday morning stroll…The saving grace was the goal just before half-time.”