The home side had 57 per cent possession and created 15 chances to Parma’s 14.
The visitors went ahead in under eight minutes when Adrian Bernabe’s first-time shot from outside the box found the bottom-left corner.
Hernani doubled Parma’s advantage in the 38th minute with a low volley into the near post via the keeper’s outstretched foot.
Stefano Negro brought the home team back to within a goal just before the break with a tap in from close range thanks to a cutback from Alessio Vita.
Parma remain on top, six points clear of their nearest rivals, Cremonese and Como.
Cittadella are seventh.
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