It took Mario Pasalic and Robin Gosens just eight minutes to overcome Napoli, as Atalanta swept away 15 points from their rivals in the top four chases with a 2-0 victory.
Atalanta went up with Mario Pasalic over Josip Ilicic against a much-changed Napoli who brought Matteo Politano back into their campaign.
The Partenopei trailed their fourth-placed rivals in the Serie A table by 12 points, but they had picked up full points in their last five league games and recently won the Coppa Italia.
Earlier in the season, the two sides challenged an exciting 2-2 draw but chances were few and far between without fans or a lot of quality on display.
Kalidou Koulibaly may have been doing well with a header when Ospina turned on an Alejandro Gomez screenshot around the corner.
Halfway through the first half, though, the Colombian was pulled off after chasing a pass into his six-yard box where he clattered into a teammate.