The former Genoa coach begins his spell in charge of the world champions with a nightmare reverse in Sicily
The Milan side's back three were particularly suspect throughout, and it was their lack of understanding that ensured that the visitors were pegged back after Diego Milito had twice given his side the lead.
Palermo strike pairing Fabrizio Miccoli and Abel Hernandez were the men who took full advantage of the Inter malaise to level the scores, before Fabrizio Miccoli and Mauricio Pinilla added stunning late strikes to complete a stunning victory.
The match began at a frantic pace, with the hosts seemingly intent on taking the game to an Inter side which looked more than a little unsure of how to adapt their new coach’s 3-4-3 formation.
Palermo captain Fabrizio Miccoli was causing particular problems by drifting into the space down the Inter left vacated by Jonathan whenever he advanced down the right flank.
While Palermo continued to dominate, they were restricted to a series of weak long-range efforts. Miccoli, with a deflected free-kick, and Josip Ilicic peppered the Inter goal with shots from distance, but neither caused Julio Cesar any real alarm.
Their inability to harness their boundless energy and convert it into tangible goalscoring opportunities was suitably punished just after the half hour when Inter snatched the lead against the run of play.
Zarate fired over a low corner which was only cleared as far as Dejan Stankovic on the egde of the box. The Serbian immediately lashed the ball back towards goal, where Milito was perfectly positioned to stick out a leg to deflect the ball past Alexandros Tzorvas to open the scoring.
However, Gasperini was not entirely fooled by his side having taken the lead and immediately replaced Zarate with Wesley Sneijder.
The game exploded into life in the second period, and no sooner had the half began than the hosts were back on level terms when Miccoli scampered onto Edgar Barreto’s lofted pass and slotted past the advancing Julio Cesar.
There was hardly time for either side to catch their breath before Inter reassumed control when Milito fired a spot-kick down the middle following Barreto’s clumsy challenge on Walter Samuel.
Amazingly, Palermo restored parity for a second time just two minutes later. Ilicic and Miccoli combined to dissect a woefully exposed and inept Inter back three, and the Palermo captain squared for Hernandez to tap into an empty net.
In the 64th minute, Ilicic blew a glorious one-on-one opportunity to give his side the lead when he fired straight at the advancing Julio Cesar, but Palermo would not be denied and scored twice in the final four minutes to secure the win.
Miccoli whipped a 25-yard free-kick into the net via the post and then, two minutes later, substitute Pinilla gave the Inter custodian no chance with a thunderous strike to make the score 4-2.
Diego Forlan marked his Inter debut with an injury time strike to pull his side back into things, but they could not find the goal needed to snatch a point, leaving Gasperini with real food for thought going into Wednesday’s Champions League clash with Trabzonspor.