Roma's mid-season struggles continued on Saturday as Rudi Garcia's men were held at home by Empoli and, with leaders Juventus also held a day later by Udinese, Napoli were able to move closer to the leading pair.
Bostjan Cesar's own-goal gave Napoli a headstart in Verona but the hosts were level at the break when Miguel Britos got in on the act with an error of his own.
However, Gabbiadini proved the hero as the recent signing from Sampdoria opened his account for Napoli with a smart finish from inside the area 28 minutes from time.
The win leaves Napoli just four points off Roma in second but five clear of Lazio in fourth after Stefano Pioli's men suffered a surprise defeat to lowly Cesena.
Having beaten bottom side Parma last time out, Gregoire Defrel's opener and a Danilo Cataldi own-goal ensured an upset at Stadio Dino Manuzzi with Milan ending their winless Serie A run against Parma.
Filippo Inzaghi's men went in search of their first league success since mid-December and gained it thanks largely to a Jeremy Menez brace either side of Antonio Nocerino's leveller.
Experienced defender Cristia Zaccardo made sure of the points with a third 14 minutes from time to move Milan up to eighth and compound Parma's troubles at the bottom of the table.
Inter endured a bad day at the office as players clashed with fans following their 3-1 defeat at Sassuolo - Simone Zaza, Nicola Sansone and Domenico Berardi on target for the hosts.
Mancini's side turned in a tepid showing and saw Inter fans hurl back their players' shirts from the crowd following a defeat in which both sides ended with 10 men.
Samuel Eto'o's Sampdoria's debut was one to forget for the Cameroonian as Torino ran out 5-1 winners at Stadio Olimpico di Torino while Atalanta and Palermo were 2-1 winners over Cagliari and Hellas Verona respectively.
