A late goal from Sergio Pellissier earned Chievo a third successive victory in Serie A, ending Roma's own run of four straight triumphs with a 1-0 home win.
A draw seemed the most likely outcome at the Stadio Marc'Antonio Bentegodi, but Pellissier struck three minutes from time to ensure the points would stay in Verona.
The result sees Roma lose ground at the top while Chievo continue to head the right way up the standings.
Fiorentina moved into the top five with a comfortable 4-1 win over local rivals Siena in a one-sided Tuscan derby.
Luca Toni and a David Pizarro penalty put Fiorentina in the driving seat within 20 minutes, with Alberto Aquilani wrapping up victory on the stroke of half time.
Reginaldo pulled a goal back for Siena, but Toni's second restored Fiorentina's three-goal advantage and took them to within two points of second-placed Inter Milan.
Siena ended the game with 10 men as Massimo Paci was shown a second yellow card, but there was no further punishment as Aquilani missed the resulting penalty.
Parma survived an early scare before three second-half goals ensured their proud unbeaten home record in Serie A remained firmly intact with a 4-1 victory against Cagliari.
Roberto Donadoni's side have now not at the Stadio Ennio Tardini in 13 league games dating back to March, although on Sunday they had to recover from going behind to Marco Sau's 20th-minute opener.
They took just a minute to equalise, through Ishak Belfodil, before putting their foot down after the break.
Jonathan Biabiany, a Jaime Valdes penalty and Belfodil's second goal late on ensured the afternoon ended comfortably for Parma as they remained inside the top half.
Cagliari have now not won in their past seven league games and are two points above the drop zone.
Catania registered back-to-back Serie A wins for the first time this season by coming from behind to beat Sampdoria 3-1.
Enzo Maresca had Samp dreaming of a possible first away win since September with an early penalty before Catania substitute Mario Paglialunga levelled after the break.
Gonzalo Bergessio boosted Rolando Maran's men into the lead with a close-range header and Catania made the points safe through Lucas Castro's effort on the stroke of full-time.
Andreas Granqvist grabbed an equaliser but Genoa could not find the winner they desperately needed in a 1-1 draw with Torino and improve their position towards the foot of Serie A.
Sweden international Granqvist nodded home after 29 minutes to cancel out Rolando Bianchi's opener for the visitors.
But Genoa could not conjure up a second, although they did have a goal chalked off two minutes into the second half when Marco Rossi was adjudged to have been offside when he poked the ball home.