Looked a little out of sorts after time out because of injury.
England players celebrate their victory.
England head coach Eddie Jones is resigned to the fact that Youngs will miss the Wales match next weekend; he is likely to send out the signal to summon Saracens 34-year-old Richard Wigglesworth into the squad.
No 8 Simmonds was highly impressive on his Six Nations debut and ran in a second late on, although the Exeter Chiefs ace may have to share the headlines to Watson after their eye-catching doubles in the 15-46 victory.
But if any team can deal with a raft of injuries, it ought to be a well-resourced England. Eddie Jones has known nothing but success in the competition during his tenure having backed up a Grand Slam triumph with their championship defence in 2017.
Italy refused to let England get away, however, and Bellini touched down in the left corner in the 58th minute following another wonderful pass from Allan.
Mike Brown, Anthony Watson, Ben Te'o, Owen Farrell, Jonny May; George Ford, Ben Youngs; Sam Simmonds, Chris Robshaw, Courtney Lawes; Maro Itoje, Joe Launchbury; Dan Cole, Dylan Hartley (capt), Mako Vunipola.
'I was really pleased with the effort today.
'At the end of the game we played some lovely rugby'.
England's training leading into Sunday's opener against Italy is said to have been intense, both during their time in Portugal last week and more recently at their Pennyhill Park base in Bagshot.
Ireland's provincial sides have impressed in Europe's Champions Cup club competition and Jones said: "I think the expectation on Ireland is high, and it's how they handle it now, isn't it?"
Pacy wing Watson claimed a brace inside 11 minutes and Owen Farrell added a third try after a superbly worked Tommaso Benvenuti score, but Tommaso Allan's penalty reduced England's lead to 17-10 at half-time.
"What annoyed me against a team that is number two in the world is we caused them a lot of problems with the ball, and I hate sitting here at the moment because we have lost and it's another statistic but in terms of what we are creating, going forward, I have a lot of hope".
How to watch England vs Italy in the Six Nations 2018.
Watson's electric pace down the right proved too much for the Italians again on 12 minutes as England were quick to brush off the disappointment of the Youngs blow.
"We always knew it was going to be a tough game, they played exceptionally well and full credit to Italy".
For Italy, under Irish coach Conor O'Shea, the goal remains one of self-respect and the need to improve on a desperate run of just one win in their last 20 Six Nations fixtures.