Lazio had playmaker Sergej Milinkovic-Savic sent off in the first half as they lost 2-1 at home to relegated Chievo in Serie A on Saturday on a disastrous day for their Champions League hopes.
Second-half goals from teenager Emanuel Vignato and Perparim Hetemaj gave the Flying Donkeys, condemned to Serie B last week with six games still to play, only their second win of the season and the first this year.
The defeat meant that Lazio dropped below Torino into eighth place with 52 points, four adrift of the top four places where they need to finish to qualify for the Champions League.
Lazio were in trouble from the moment that Milinkovic-Savic was given his marching orders in the 34th minute for lashing out after being fouled by Mariusz Stepinski.
Vignato, 18, curled in his first Serie A goal in the 49th minute and Hetemaj headed the second two minutes later.