The reigning champions got their 2018 campaign off in style with a bonus point 46-15 win in Rome with Exeter Chiefs' Simmonds, who was making his debut in the Six Nations, grabbing two tries in the game.
Anthony Watson also scored two tries, while Owen Farrell, George Ford and replacement Jack Nowell crossed for England, but Jones was quick to highlight the performance of Simmonds afterwards.
The Australian, who is waiting on news of the knee injury scrumhalf Ben Youngs picked up with one eye on the clash against Wales at Twickenham next weekend, said: "When the game opened up he was in his element.
"He's got gas. He does all our speed work with the backs. He's a great discovery for us and gives us great options at No 8."