Scorers: Zola 23 (C), Esposito 40 (C), Suazo 47 (C)
Roma's crisis continues with a humiliating defeat in Sardinia, as Cagliari took advantage of disastrous defending.
The last time these two teams met at the Olimpico Cagliari were thrashed 5-1, so they were eager for revenge in Sardinia. Roma were still fuming from their controversial 2-1 defeat to Juventus last week and had to do without Ivan Pelizzoli, Christian Panucci and the suspended Amantino Mancini, so former Liverpool defender Abel Xavier made his Serie A debut.
Alessandro Agostini, Nelson Abeijon and Daniele Conti return from a ban to shore up the Rossoblu squad following their last-gasp loss at Parma. It was a special moment for Conti, as his father - Giallorossi legend Bruno Conti - was in the stands celebrating his 50th birthday. Mauro Esposito was able to start despite suffering from flu.
Antonio Cassano's clear offside position saw an early goal disallowed for Roma, while Abel Xavier found it difficult to deal with Esposito's pace.
Francesco Totti's free kick shaved the frame of the goal and Cassano saw timid penalty appeals for Maltagliati's challenge waved away.
However, it was Cagliari who took the lead thanks to some woeful defending. Matteo Ferrari's clearance from a long Maltagliati free kick fell to Gianfranco Zola and his less than irresistable effort took young goalkeeper Carlo Zotti by surprise at the near post.
Zotti was again insecure when he parried a fierce David Suazo strike with his chest and was fortunate there were no Cagliari players to tap in the loose ball.
It was no real surprise when the Sardinians doubled their lead from a Zola free kick. Only Esposito reacted to Conti's free header and tapped in from less than six yards as the entire Roma defence and goalkeeper Zotti were caught ball-watching.
There was bad news soon after, as Zola limped off with a suspected thigh strain. Traianos Dellas was booked for hacking down Esposito and will miss the Milan game.
Suazo had another good chance to make it 3-0 only to fire straight at Zotti, while Vincenzo Montella failed to make the most of a defensive error.
Cristian Chivu made his first appearance of the season in the second half, returning after two operations on a fractured bone in his foot. It wasn't a good start, as two minutes after he came on to the pitch Cagliari scored their third. Gobbi threaded through for David Suazo, whose low drive went in despite Zotti getting a touch.
Roma's nightmare got even worse when Daniele De Rossi was dismissed for a challenge from behind on Suazo. Simone Perrotta's fierce long-range effort was blocked by Gennaro Iezzo, but the Giallorossi couldn't seem to get back into the game.
Cagliari: Iezzo; Agostini, Bega, Maltagliati, Lopez; Gobbi, Budel (Albino 74), Conti (Alvarez 71); Zola (Langella 45), Suazo, Esposito
Roma: Zotti; Xavier, Dellas (Chivu 46), Ferrari, Cufre; Dacourt (Aquilani 56), De Rossi, Perrotta; Totti, Cassano, Montella (Cerci 73)
Ref: Collina
Sent off: De Rossi 58 (R)