Cristiano Ronaldo (R) celebrates Marcus Rashford (C) | AFP
Manchester: Marcus Rashford struck with virtually the last kick of the game to take Manchester United into the Premier League top four at West Ham's expense with what Ralf Rangnick described as a "massive" 1-0 win on Saturday.
United were insipid as an attacking force for 93 minutes at Old Trafford, but found the breakthrough at the death as all three of Rangnick's substitutes combined when Anthony Martial and Edinson Cavani teed up Rashford for a tap in at the back post.
"The atmosphere (in the dressing room) is amazing. Quite rightly the boys were celebrating, they know what a massive win this was," said Rangnick. "Those are the best kind of wins when the other team has no time to come back."
Victory lifts United a point above the Hammers and sees the Red Devils leapfrog Tottenham and Arsenal in the battle for Champions League football next season.
The winner was also a huge moment for Rashford, who has looked devoid of confidence in recent months.
The England international scored for the first time since October in a 3-1 win at Brentford on Wednesday and was in the right place at the right time for what could be a decisive moment in United's desperation not to miss out on the riches and prestige of Champions League football next season.
Rashford was again left out of Rangnick's starting line-up in favour of 19-year-old Anthony Elanga.
However, he was the first of three changes made by the German after the break, who all played a part in the winning goal.
Rangnick claimed that Martial had refused to be part of his squad for last weekend's 2-2 draw at Aston Villa as he looks for a move away from the club for more game time.
The Frenchman publicly denied that accusation and was given his first minutes under the interim boss when he was introduced along with Cavani in the final 10 minutes.
Martial played in Cavani on the left of the box and the Uruguayan's cross just required a touch from Rashford at the back post.
The wild celebrations survived a VAR check against Cavani for offside and there was barely time for West Ham to kick-off in what could be a fatal blow to their outside hopes of reaching the Champions League for the first time.
"We had to take some risks in the last 15 minutes but in the end I wanted to show the players it is about winning this game and I'm more than happy we scored the goal in the last minute," added Rangnick.
"I am very pleased the three subs prepared the goal and scored the goal."
Rangnick has lost just one of his 10 games since taking temporary charge till the end of the season, but once again the result was more impressive than the performance from United.
Alphonse Areola was drafted in to the West Ham goal in the absence of Lukasz Fabianski due to a positive test for coronavirus, but the Frenchman was forced into just one serious save when he turned Fred's driven shot behind early in the second half.
West Ham also did little to test David de Gea, bar a late long-range effort from Declan Rice that nearly caught the Spaniard napping.
But David Moyes still believed his side had done more than enough to earn at least a point.
"It's not easy when you lose a goal in the last second. It was certainly avoidable," said Moyes.
"A draw would have been a good result as we hadn't played well enough to score goals, but we certainly kept Man Utd out enough to get the draw."