Nelson made virtually every yard of the running to inflict a surprise defeat on fellow Aidan O'Brien-trained runner The Pentagon in Leopardstown's P.W. McGrath Memorial Ballysax Stakes.
The Pentagon was the choice of Ryan Moore and was sent off the 13-8 favourite for the Group Three heat, but he proved no match for the Donnacha O'Brien-ridden Nelson.
Positive from the off, O'Brien asked his mount to respond as another Ballydoyle inmate, Delano Roosevelt, started to press his claims in the home straight and the winner eventually proved half a length too good.
Nelson, a son of Frankel out of Irish Oaks winner Moonstone, was cut to 16-1 from 25s for the Investec Derby by RaceBets, while The Pentagon, who finished a length third, was pushed out to 12-1 from 7-1 by 32Red.
O'Brien said: "You'd be delighted with that, it's tough going out there.
"Donnacha was delighted with his horse and said he stays well. Seamus (Heffernan, rider of Delano Roosevelt) was very happy with his horse and said he just got a little bit lonely when he got there.
"Ryan was very happy. He said of all our horses he rode, he wants real nice ground, but he'll come on a ton. It was great because you need to get the racing miles into them.
"Nelson handles soft ground looking at that. Obviously, we had to have something to make the running and he's the fella that held up his hand and said he wouldn't mind going on.
"He had gone forward in his races before and won around here before making the running.
"He'll come back for the Derrinstown and that's what they'll probably all do."