Whites head coach Garry Monk made ten changes to his side and handed debuts to Billy Whitehouse and Paul McKay as the likes of Chris Wood, Pontus Jansson and Kyle Bartley were all rested.
And after being outplayed throughout the entire first half, Leeds fell behind in the 54th minute when Lewie Coyle upended Roarie Deacon in the area and Jamie Collins calmly stroked home the penalty.
United never once looked like equalising and the Whites were then made to finish the game with ten men when captain Liam Cooper was sent off for picking up a second yellow card.
Sutton made their intentions clear in the second minute when Craig Eastmond crunched into Matt Grimes and after just six minutes the home side had the ball in the back of the net but Roarie Deacon’s clinical rising finish was ruled offside.
A long ball over the top had centre-backs Liam Cooper and debutante Paul McKay chasing shadows but Leeds were saved by the assistant referee’s flag, just as Sutton’s home faithful began to celebrate.
The non-league hosts were on the front foot and only a fine save by Silvestri denied Sutton an opener six minutes later as the Italian tipped a fine 25-yard effort from Deacon again over the bar.
Cooper then got himself in a mess and was booked for taking down Bedsente Gomis as Sutton continued on the front foot and Gomis then went mightily close to breaking the deadlock just before the half hour mark when his low shot from six yards out was stopped by Silvestri’s backside.
Leeds responded by finally creating their first chance but an attempted lob from Stuart Dallas did not carry enough height to clear ‘keeper Ross Worner.
United’s Tyler Denton then entered the book for fouling the troublesome Deacon but Denton then fed Dallas whose low shot was deflected wide as Leeds threatened to get going.
The lively Denton was then inches away from bagging Leeds a 40th-minute penalty but Deacon’s foul after the left back’s surging run forward was just outside the area and Kalvin Phillips saw his free kick saved.
But Sutton remained a threat and only another strong save by Silvestri kept out a thunderbolt from Deacon shortly before half time.
Leeds then began the second half on the attack but after jinking inside from the right flank, Whitehouse saw his low shot deflected wide for a corner which was cleared.
And just three minutes later Sutton took the lead when a long ball from Nicky Bailey had United’s chasing defence in disarray, so much so that Coyle fouled Deacon to concede a penalty.
In an attempt to deal with the danger, Coyle and Silvestri collided with each other and Coyle then caught Deacon who was spent sprawling to the ground as referee Stuart Atwell pointed to the spot.
Captain Jamie Collins stood up to take the penalty and sent Silvestri the wrong way to give Sutton a 54th-minute lead.
The Leeds response was limited, despite head coach Garry Monk bringing on Hadi Sacko for Dallas and then another debutante in Mallik Wilks, on for Doukara and playing just three days after his brother was killed in Harehills on Thursday afternoon.
Kemar Roofe was then introduced for Whitehouse in one final throw of the dice, shortly after Sutton had seen claims for a second penalty waved away for handball.
A total waste of a 77th-minute free-kick by Matt Grimes summed up his and United’s afternoon.
And things went from bad to worse in the 83rd minute when Cooper took out Craig Eastmond with a late sliding tackle and was inevitably sent off after picking up a second yellow card.
Adam May then went close to adding Sutton a second when whipping a fierce shot just wide and Leeds rarely threatened in a generous five and a half minutes of injury time with Marcus Antonsson ballooning a wild shot over the bar.
Leeds United: Silvestri, Coyle, McKay, Cooper, Denton, Grimes, Phillips, Whitehouse (Roofe 73), Dallas (Sacko 57), Doukara (Wilks 64), Antonsson. Subs not used: Peacock-Farrell, Vieira, Ayling, Vann.
Sutton United: Worner, Amankwaah, Collins, Gomis, May (Traore 90), Eastmond, Bailey, Spence, Deacon, Biamou, Downer. Subs not used: John, Fitchett, Gueye, Monakana, Tubbs, Shaw.
Referee: Stuart Atwell.