Sergio Floccari almost handed the home side an early lead, but his deflected strike from the edge of the box shuddered the underside of the bar before bouncing away to safety.
Just minutes before the break, Matias Vecino wasted a great opportunity to double his side's lead as he struck the foot of the post from a few yards out.
Zielinski then hit the woodwork once more for the visitors moments after the restart and Empoli's profligacy in front of goal came back to haunt them.
Nonetheless, the young forward's blushes were spared by Floccari, who fired Sassuolo ahead just two minutes after Berardi's miss.
Berardi then found then back of the net himself with a 74th-minute header to allow the home side to coast to victory.