Lazio's Serie A title hopes all but evaporated in a 2-1 loss at relegation-threatened Lecce, who also missed a penalty and had a goal disallowed on Tuesday.
And Lazio's bad night was complete when Gil Patric was red-carded in stoppage time after the video assistant referee saw him bite Lecce's Giulio Donati.
Fabio Lucioni and Khouma Babacar scored for Lecce after Felipe Caicedo had given Lazio an early lead.
Second-place Lazio remained seven points behind Juventus, who play at AC Milan later and could take a huge step towards a ninth successive Serie A title.
Lecce moved out of the relegation zone, a point above Genoa, which hosts Napoli on Wednesday.
Lecce thought it had taken the lead after two minutes through Marco Mancosu but it was ruled out for handball in the buildup.
Instead, Lazio took the lead moments later when Lecce goalkeeper Gabriel slipped under pressure from Ciro Immobile. He still managed to parry the first Lazio attempt but Caicedo hit the rebound into an empty net.
Lecce levelled on the half hour mark when Babacar was left unmarked, eight yards out, to head in Filippo Falco's cross.
The home side had a great chance to take the lead in first-half stoppage time but Mancosu blasted a penalty over the bar, following handball from Patric.
However, Lecce did go in front two minutes after the break when Lucioni headed in a corner.
Gabriel atoned for his early error with several saves to keep Lecce in front, including stopping Bobby Adekanye's header from point-blank range, four minutes from time.
Australian Associated Press