The Giallorossi have now lost three of their last four Serie A matches to risk falling out of contention for the Champions League places.
Roma was also recently eliminated from this season’s Champions League by Porto, which resulted in the firing of coach Eusebio Di Francesco and the departure of sporting director Ramon “Monchi” Rodriguez.
Milik had the goal of the day, using a splendid backheel control before spinning around to score from close range.
Roma midfielder Steven Nzonzi had a chance to pull one back for Roma in the second half but he headed onto the crossbar before an open net.
Napoli’s only concern was an apparent injury to Mertens that meant the Belgium international had to come off in the second half. But Mertens said afterward that it was only a slight knock to his knee.
“We deserved the win and it’s too bad we didn’t score more goals in the first half, too,” Mertens said. “We are continuing to develop as a team.”
Roma dropped from fifth to sixth and now trails fourth-placed AC Milan by four points.
The top four finishers qualify for the Champions League.
Parma went ahead early through Gervinho but Mario Pasalic quickly equalized before Zapata’s decisive goals gave him 19 for the season, tied with Cristiano Ronaldo and Krzysztof Piatek for second on the league chart behind only Fabio Quagliarella’s 21 for Sampdoria.
Francesco Vicari scored early with a header for Spal, while Frosinone was unfortunate to hit both the post and crossbar.
Source: FOX Sport