England's 'great discovery'
Simmonds grasped his opportunity with both hands after starting at No.8 in the absence of the injured Billy Vunipola and Nathan Hughes at Stadio Olimpico.
The pacy back-row scored a second-half double and also provided an assist in a superb all-round display in Rome, where Anthony Watson (two), Owen Farrell, George Ford and Jack Nowell also went over.
Jones was delighted with the impact Simmonds made in his tournament bow after watching his side start the defence of their title with a bonus-point win.
"When the game opened up he was in his element," said the England head coach. "He's got gas and he does all our speed work with the backs as he’s that quick.
"He's a great discovery for us, he gives us great options at No.8."
Italy made a game of it before tiring late on, England taking advantage by scoring three tries in the last 13 minutes.
"It's a very positive start," said Jones.
"We always knew it was going to be a tough game, they played exceptionally well and full credit to Italy. Conor O'Shea is doing a great job coaching them and it was a good tough game of rugby and we ran away with it in the end."
England’s victory may have come at a cost, as scrumhalf Ben Youngs suffered a knee injury in the first half.
