The final 10 minutes remained and both teams looked as likely as each other to grab an extra goal, as a second crunching, last-ditch challenge in a matter of minutes flew in, this time from Christian Kabasele as he denied Martial the chance to shoot from 12 yards.
Again both teams made changes at the same time in the 83rd minute, as Jose Mourinho withdrew Sánchez for the more defensive-minded Scott McTominay – looking to shut up shop – and Adam Masina made his Premier League debut, coming on for Jose Holebas.
Shortly after, Javi Gracia made his final change, and an attacking one at that, replacing Cathcart with Isaac Success.
A minute before the end of regular time, Doucouré had yet another long-range effort saved and held at the near post by De Gea.
Just three minutes of added time saw relentless attacking play from the Hornets, as Mourinho made his third and final change, replacing Valencia with Eric Bailly as an aerial bombardment from the home side loomed.