With a single attack mode activation totalling eight minutes available, the strategic aspect of the second race was immediately different to the first, and Evans held off on taking his 250kW power mode until late on in the race.
But it was a minute away from coming undone, with the late safety car brought out on lap 18 for Alexander Sims' stranded Mahindra meaning that Evans was unable to take it - leaving the Jaguar driver relying on the new added time regulations to help him out.
With Sims' car cleared swiftly, and an extra three minutes added on in addition to an earlier 2m15 pencilled in for the first-half safety car brought out for Antonio Giovinazzi's unresponsive Dragon Penske machinery, Evans was able to collect his attack mode on the 20th lap and see out the full eight minute run-time.
But that played into his hands in the business end of the race; Evans dropped behind Vergne after taking the attack mode line at the Marconi hairpin, but re-passed the French driver and immediately caught up to the leading pack.
With Andre Lotterer leading Robin Frijns ahead on the regular race power mode, Evans was able to pick Frijns off at Turn 4 on lap 22, and immediately dispatched Lotterer on the uphill run to Turn 7 to cement the lead.
Evans was in control from there and immediately began to break-build, but a skirmish between Sam Bird and Nick Cassidy on the ante-penultimate lap at Turn 7 left the Envision driver in the wall after he'd scythed through the field and battled with the British driver for sixth place.
The Porsche Taycan safety car made its third appearance of the race, although Cassidy was eventually able to free himself from the wall to ensure a last-lap shootout between Evans and Vergne, who had been able to manoeuvre his way through Frijns and Lotterer.
But Evans had two percent more energy in his allowance for the last lap than the Techeetah driver, and thus was able to keep Vergne at bay to chalk up a second victory on the bounce.
Evans had passed polesitter Vergne earlier in the race for the lead after clearing Jake Dennis and Andre Lotterer within the first seven laps, stealing a tow after the first safety car to clear the two-time champion for the lead, but an attack mode-augmented Frijns shuffled his way past Evans.
Frijns then continued to lead the middle portion of the race, but ran out of attack mode just as Lotterer was beginning to home in, with the Porsche driver using his a minute-and-a-half advantage to clear the Dutchman.
Once the two had been cleared by Vergne, Frijns re-passed Lotterer at the start of added time to collect a second trip to the podium in Rome.
Lotterer finished fourth ahead of Stoffel Vandoorne, despite earlier confusion ahead of the last safety car where Vandoorne made his move on the German at the Marconi hairpin.
Vandoorne was instructed to give the place back, which Lotterer then held through the final lap as the Belgian had to be content with fifth.
Pascal Wehrlein finished sixth, benefitting from a five-place penalty for Lucas di Grassi - who was handed a five-second time penalty for contact with Dennis at Turn 4.
Oliver Turvey bagged a hatful of points for NIO 333; the British driver was sitting around five seconds behind the leading pack of cars, but the late safety car brought him back into contention and allowed him to also benefit from di Grassi's penalty - as well as a 10-second penalty for Nyck de Vries for causing contact with Sergio Sette Camara.
Di Grassi collected eighth place to salvage something for Venturi after Edoardo Mortara retired early on having hit the wall at Turn 3, with Sebastien Buemi collecting two points for Nissan e.dams.
Oliver Askew was classified in 10th - 0.7s clear of Dan Ticktum - but a post-race five-second penalty for overtaking under the safety car demoted him to 11th.
