By half-time, Sutton were 3-0 up thanks to goals from Mitch Whiley and Ryan Worrall’s double and Mitch Whiley’s strike.
In the second half, Louth piled on the pressure as a change of formation put Sutton under some intense pressure.
On a hot day, thing got tougher for Sutton when Cam Ward was shown a straight red for violent conduct, and Louth, now with their tails up, scored twice in quick succession.
Rovers were under the cosh, but their quick build-up and raw pace saw Worrall square the ball for Riley Hall who finished in an empty net.
Sutton were now cruising and 10 minutes from time, Whiley’s brilliant chipped through ball allowed Worrall to lob the on-rushing keeper to complete his hat-trick.
Man-of-the-match was awarded to captain Adam Henshall.
Manager Rob Bedford said: “This was a very good result and our best performance all season.
“We dominated from the off and showed character when going down to 10 men and conceding two quick goals.
“Scoring quickly after the second was vitally important.”
He added: “It was a brilliant effort from all the lads and they thoroughly deserved the win to amend last year’s loss in the same trophy final.”
The club wishes to thank their sponsors Mablethorpe Seal Sanctuary, and Seacroft Ford.