United and West Ham will meet again in an FA Cup replay after a late Anthony Martial equaliser cancelled out Dimitri Payet's controversial opener.
Payet had put the East London outfit ahead through an exquisite free-kick- although he shouldn't have been on the field at that point- before a late rally led to Martial's 83rd minute strike to deservedly take us back to Upton Park.
United had dominated the game but lacked a cutting edge and it was the visitors whom went close early on through an Andy Carroll header.
David de Gea saved well from Emmanuel Emenike whilst Jesse Lingard and Marcus Rashford had half-chances at the other end.
Ander Herrera volleyed wide from a Martial cut back and the Spaniard should then have done better following neat build up between the Frenchman and Marcos Rojo.
West Ham- backed noisily by their 7,000 strong travelling support- ended the half well as Aaron Cresswell forcing a smart save from the sprawling De Gea.
United had a penalty appeal turned down when Herrera's goalbound drive bounced off the arm of Winston Reid, before Payet appeared to commit a dive under the attentions of Rojo inside the area.
The playmaker had already been booked and was lucky not to receive a second, but it was he whom conjured up a moment of magic to break the deadlock on 68 minutes.
The Frenchman unleashed an unstoppable 25 yard free-kick that left De Gea with no chance and put Slaven Bilic's side within sight of Wembley.
Louis van Gaal introduced Bastian Schweinsteiger and Memphis and the changes instantly worked dividends as United upped the tempo and ante in pursuit of a leveller.
Guillermo Varela blocked Payet when one on one, but the hosts built a spell of pressure which saw Schweinsteiger lash off target and Memphis go close with a snapshot.
With seven minutes left, United got reward for the belated pressure as Herrera crossed from the right and Martial stole in at the back post to hook home.
Michael Carrick fired narrowly wide as the Reds went in search of a winner, but West Ham remained a threat themselves and United needed a brilliant save from De Gea to deny Michail Antonio in stoppage time.
A flurry of corners from the visitors led to nothing and both sides will be reasonably happy with a draw as they prepare to meet again for the right to go to Wembley.
Overall team performance: 7/10
United Faithful Man of the Match: Guillermo Varela