If Rafael Benitez's team had beaten Sassuolo, Cagliari, Udinese, Bologna and Chievo as expected, they would be only two points behind leaders Juventus with nearly half the season still to play.
Instead they drew against all five teams and, rather than chasing Juventus, are now looking over their shoulders at Fiorentina, who are challenging them for third place which earns a spot in the Champions League playoff round.
Atalanta, who host Napoli on Sunday (1400 GMT), are 12th with 24 points from 21 games, just the type of team Napoli (44 points) are prone to slip up against.
Benitez, who has rebuilt Napoli this season with the 64 million euros the club earned by selling Edinson Cavani to Paris St Germain, has been exasperated as a combination of sloppy defending and erratic finishing have cost his team crucial points.
Despite the slip-ups, the former Liverpool, Chelsea and Inter coach sees a bright future for the club especially after signing Brazilian midfielder Jorginho from Hellas Verona during the January transfer window.
"Jorginho has personality," he said. "He's not afraid of making mistakes, he's a player with qualify who can do very well here.
"We've brought him to Napoli because he's different to the midfielders we already have and gives us tactical alternatives.
"We are in a phase where we are growing and I'm very positive for the future," added the Spaniard. "We have players in the team who can player at the top level for another four or five years.
"We are among the top three in Italy and this is a great chance to carry on with our project and aim higher."
The clubs, bitter rivals at the best of times, had already agreed terms for Inter midfielder Guarin to swap with Juve forward Vucinic when the Milan club pulled the plug following protests by their fans.
Inter, who are fifth with 33 points and are just one clear of Torino, Parma and Hellas Verona, have won only one of their nine last matches while Juventus, six points clear of AS Roma, have won 18 out of 21 games this season.
Inter won 3-1 at the Juventus stadium on their last league visit but that heralded a long, steady decline which eventually saw them finish ninth last term and earned coach Andrea Stramaccioni the sack.
Second-placed Roma, who have scored 10 goals in winning their last three games, host Parma as they attempt to keep up the pressure on Juventus after cutting their lead from eight to six points last Sunday. Fourth-placed Fiorentina (41 points) visit Cagliari on Saturday (1700).)
- Sports & Recreation
- Hellas Verona
- Inter Milan
- Rafael Benitez