An enjoyable evening for the Italians soon turned sour for Giorgio Chiellini who thought he had given Italy the lead in the 20th minute. Instead, his strike was ruled out by VAR to keep the scores level.
Things turned from bad to worse for the Juventus defender when he was forced to leave the field just minutes later with a hamstring injury.
Despite losing their leader, Italy instantly took the lead through a brilliant move that was started and finished by Locatelli. The player fired home from close range after immense build-up play with Dominico Berardi.
Just minutes after the restart, Locatelli bagged his second of the night to put Gli Azzurri two goals to the good.
Receiving a lay-off from Nico Barella, the midfielder steadied himself before unleashing a well-placed strike into the far-left corner of the Switzerland goal.
Ciro Immobile added a third with just minutes to go, polishing off a classy affair for the Italians.
Another routine victory for Mancini's side keeps them comfortably top of Group A. The result also extends their undefeated streak to 29 games. Switzerland, meanwhile, are in trouble with only one point from their opening two matches.
You can read a full match report on our sister site Football365.
What's next for Italy and Switzerland?
Another convincing victory for Italy sees them become the first side of the tournament to qualify for the knockout rounds. They will look to make it three wins from three against Wales in Rome on Sunday.
With just one point to their name, Switzerland must defeat Turkey to have any hopes of qualifying.
Stat of the Day
As per OptaJoe, at 23 years and 159 days only Giacomo Bulgarelli (v Switzerland in 1962) and Mario Balotelli (v Germany in 2012) have scored a brace for Italy at a major tournament at a younger age than Manuel Locatelli this evening (23y 159d).
Coming up on Thursday
Having both lost their opening games in the group, three points will be pivotal for either side to get off the mark and ensure their contention for progression.
In terms of the opposition, Denmark need to beat Roberto Martinez's side to have realistic hopes of qualifying.
Last weekend, Romelu Lukaku struck twice for the Red Devils in a convincing 3-0 win over the Russians. The Inter Milan striker will be determined to improve upon this tally in his bid for the Golden Boot.
Lukaku himself has confirmed that both sets of players and fans will dedicate the tenth minute of the match to Danish midfielder Christian Eriksen who suffered a cardiac arrest on the pitch in his side's defeat to Finland.
Three points for the Austrians will put them in pole position to qualify for the Euros knockout rounds for the first time in their history.