Cagliari again left it late thanks to Ragatzu's 90th-minute equaliser having grabbed victory against Sampdoria on Monday five minutes into added time.
The Sardinian side move fourth, four points behind third-placed Lazio, and level on 29 points with fifth-placed Roma.
Fiorentina fell to their fourth consecutive defeat, 2-1 at Torino, with coach Vincenzo Montella under increasing pressure with the Tuscan side just five points above the relegation zone.
Inter Milan remain top after their goalless draw against Roma on Friday with champions Juventus two points behind after falling to their first defeat of the season 3-1 at Lazio on Saturday.
Napoli were poor again and just a bit of remaining pride let them draw at Udinese, while Milan at least got a good win at Bologna's home 1-3.
Spal lost home 0-1 to Brescia and so have fallen lonely at last spot. Brescia hadn't been winning a game since September.