Massimiliano Allegri's tenure as coach of Serie A giants AC Milan came under fresh scrutiny when the Rossoneri suffered their third defeat of the season in a 2-1 reverse away to Udinese.
Milan opened their campaign with defeat at home to Sampdoria and have failed to win or score any goals at the San Siro in three attempts including the scoreless draw against Champions League opponents Anderlecht.
Reports have since suggested only a win on Sunday would save Allegri's job, but that was of no concern to Udinese, who started the day fourth from bottom.
Loss of form
The hosts opened the scoring in the 40th minute when giant Swedish striker Mathias Ranegie rose to send a header under the crossbar of beaten keeper Christian Abbiati.
Italy under-21 international Stephan El Sharaway levelled for the visitors 10 minutes after the restart with a right-footed shot from outside the box that lodged in the left hand corner of the net.
But from then on, things got worse for the seven-time European champions.
The game-changer came in the shape of a red card for Milan's Colombian defender Cristian Zapata, who was sent off for a second bookable offence after a foul from behind on Ranegie in the box.
The referee pointed to the spot and striker Antonio Di Natale stepped up to beat Abbiati with a low drive to put the hosts in the lead.
Milan's hopes of levelling suffered a blow seven minutes from time when they were reduced to nine players after Kevin Prince Boateng was sent off for a second bookable offence.
A day after champions Juventus underlined their title credentials in emphatic style with a 2-0 home win over Chievo, it was a disastrous day all round for Milan's clubs.
Saturday 22 September
Parma 1-1 Fiorentina
Juventus 2-0 Chievo
Sunday 23 September
Sampdoria 1-1 Torino
Udinese 2-1 AC Milan
Catania 0-0 Napoli
Atalanta 1-0 Palermo
Bologna 1-1 Pescara
Inter Milan 0-2 Siena
Cagliari v Roma – pp
Inter Milan started the day six points behind Juve and finished it with the same deficit after suffering a shock 2-0 defeat at home to Siena.
Simone Vergassola silenced the San Siro when he opened the scoring in the 73rd minute and midfielder Francesco Valiani came off the bench to inflict further damage with a goal on the stroke of full-time.
Inter's defeat is unlikely to be consolation for Allegri or his side, who now sit 15th in the Serie A table ahead of the late match between Lazio and Genoa.
Elsewhere on Sunday struggling Pescara grabbed a share of the points in a 1-1 draw at Bologna while Atalanta beat Palermo 1-0 at home to leave the Sicilians second from bottom.
Napoli's 0-0 draw away to Catania means that for the first time this season Juve have opened up a gap, two points, on their closest challengers from Naples.
Only Lazio can pull level on points with the champions if they beat Genoa later.
Sampdoria failed to win for the first time this season when they were held at home by Torino.
The Cagliari v Roma match was controversially postponed hours before kick-off after the Sardinian club's president invited fans to the match despite an official decision for it to be played in an empty stadium.