Both sides have stuttered so far this season, Spezia thrashed 4-1 at Inter and missing injured Daniel Maldini, Kelvin Amian and Salva Ferrer. Sassuolo were still without Hamed Junior Traore and Mert Muldur to long-term injuries.
M’Bala Nzola turned his marker to fire over on the half-volley from 12 yards, but the deadlock was broken when Kyriakopoulos burst down the left and floated a cross to the back post where Davide Frattesi was waiting for a free header.
Moments later, Spezia drew level as Arkadiusz Reca saw his pull-back from the left deflected, but it only went as far as Simone Bastoni to curl brilliantly first time into the top corner from 14 yards.
There was a mad scramble during a corner and Spezia received a penalty following a VAR review for the Gian Marco Ferrari handball. Nzola sent Andrea Consigli the wrong way to convert the spot-kick on the stroke of half-time.
Sassuolo equalised thanks to a huge misunderstanding in the Spezia defence, as Bartlomiej Dragowski rushed out to clear the Jeremy Toljan pass, but crashed into teammate Mattia Caldara, allowing Andrea Pinamonti to waltz it into an empty net.
Spezia 2-2 Sassuolo
Frattesi 27 (Sa), Bastoni 30 (Sp), Nzola pen 45 (Sp), Pinamonti 50 (Sa)
Sent off: Ekdal 81 (Sp)