United's under 18s bounced back from a disappointing defeat to Wigan with an emphatic 5-2 win at Cardiff City.
After falling behind in the first half, the Blades raced into a 3-1 second half lead, adding another two in stoppage time after the hosts had set up a nervy finale with 15 minutes to go.
United started the better of the two teams as Andre Brooks fired over inside a minute, before Theo Williams went closer when he forced a save from the Cardiff goalkeeper.
Ryan Viggars, making his first appearance of the season, saw two efforts saved before the Blades fell behind when James Crole fired home latching onto a ball over the top.
Viggars was once again thwarted twice before United hit back when Ayari got his first of the afternoon, taking down Viggars' cross field pass after Tom Angell won the ball back in defence.
United came out flying after the break and by the time the hour mark had just passed, Del Geary's side had a 3-1 lead.
Ayari got his second with a powerful low effort from outside the box, before Beau Anderson headed home his first under 18s goal, heading home Andre Brooks' corner.
But Cardiff set up a tense finale when Ashford fired home a near-post effort, before a big chance went a miss for the hosts just minutes later.
With both teams missing chances to add further goals, United sealed the points when Brooks slotted home in the 90th minute, and substitute Will Osula scored moments later, curling home after picking up Ayari's pass into the box.
Geary: "We've shown good character again to come from behind. At the end of the day, every single one of these kids gives everything and that's all I can ask. There's going to be good play and bad play, but I know I'm sending out a group who will give 100% for themselves and the football club. They should go home proud of themselves tonight."
Blades: Chapman, Skerritt, Angell, Arblaster, Cullinan, Anderson, Th. Williams (Smith 75), Ayari, Viggars, Marsh (Osula 70), Brooks.
Unuse: Hiddleston, Slater, Nesbitt.