Goals from Nahitan Nandez, Giovanni Simeone, Radja Nainggolan and Joao Pedro saw the Isolani move within four points of a Europa League qualification spot as they won their first league game on home soil since December.
A close-range Gleison Bremer finish and an 11th Serie A goal of the season for Andrea Belotti ensured that the hosts had to work hard for their victory in an enthralling contest.
The first half ended with Casteddu leading 2-0 after Zenga’s 3-5-2 formation seemed to provide the right balance against a Torino side that struggled to get going.
Nandez gave Cagliari the lead on the 12th minute with a fantastic volley after a corner was half cleared to the edge of the area where the Uruguayan stood waiting to finish with aplomb.
The hosts soon doubled their lead, Giovanni Simeone with his third goal in as many games after Charalampos Lykogiannis got forward well down the left flank to tee up the in-form striker for a tap-in.
Belotti looked destined to pull one back for the Toro but his effort was saved well by Alessio Cragno after the former had released an effort from close range.
The home side thought they’d won a penalty for a Nicolas Nkoulou handball as the half drew to a close, but referee Maurizio Mariani reversed his original decision after a lengthy VAR check, having decided that the ball had hit the defender’s shoulder.
Cagliari exploded into action in the second half when captain Nainggolan extended their lead with a left-footed strike from the edge of the area that left Salvatore Sirigu with no chance in the Torino goal.
The visitors pulled another back through Bremer after Ola Aina had knocked down a Cristian Ansaldi cross soon after the latter had stepped onto the pitch in place of Lorenzo Di Silvestri.
Belotti exquisitely hammered home a Simone Verdi corner on the 65th minute to give Moreno Longo’s side hope of a comeback as the home side began to look increasingly tired.
However, Zenga’s side further extended their lead when Nkoulou did give away a penalty after his lazy tackle brought down substitute Luca Pellegrini in the box and Joao Pedro stuck away his 17th league goal of the season from the spot.
The game drew to a close with the side from Turin looking for further consolation but Zenga’s side held out and his first home game on the island of Sardinia ended exactly as he’d have dreamt, minus the supporters of course.