An Alberto Paloschi strike in the 61st minute handed Chievo a shock 1-0 win and derailed Lazio's Serie A title hopes on Saturday.
Lazio, sitting five points behind leaders Juventus in third, were expected to close the gap to the leaders in Rome's Olympic stadium.
But despite dominating for long periods, Vladimir Petkovic's side, playing with German veteran striker Miroslav Klose, ultimately failed to find a way through the Chievo defence and left the pitch to a chorus of jeers and whistles.
Antonio Candreva skewed an angled drive wide after being set-up Sergio Floccari and then Frenchman Abdoulay Konko saw his close range shot saved by 'keeper Christian Puggioni.
Lazio had limited Chievo's offensives in the opening period, but were stunned when the visitors scored a well-deserved goal just after the hour.
French midfielder Cyril Thereau found space on the edge of the Lazio box and cut the ball back for Bojan Jokic. The Slovenian's first-time drive came off the crossbar and Paloschi was on hand to tap home the rebound.
The goal took the wind out of Lazio's sails and they were left even more frustrated after chances by Andre Dias and Stefano Mauri went begging.
Juventus host Genoa in Saturday's late match with the chance to extend their lead over second-placed Napoli to eight points. Napoli travel to Parma on Sunday.