Ghanaian midfielder Kevin Prince Boateng was sent off as AC Milan's season slumped to a new low on Sunday as lost 2-1 at Udinese on Sunday.
Milan had two players sent off as their chances of catching leaders Juventus fades.
It was their third defeat in four Serie A games with Boateng comounding their problems.
Roberto Di Natale scored the winner for Udinese with a 68th minute penalty, while the visitors had Cristian Zapata and second-half substitute Boateng dismissed.
Milan have not won a game at San Siro this season in any competition in five attempts.
Milan were facing opponents who, like themselves, are struggling to rebuild after selling their top players during the close season.
Udinese, who had not previously won a game this season in any competition, went ahead five-minutes before the break when Swedish striker Mathias Ranegia scored from close range following a free kick.
Boateng, rested from the starting line-up, came on in the 52nd minute and had an immediate impact as he was involved a move which ended with Stephan El Shaaraway rifling the equaliser from 30 metres.
Milan, who channeled too much energy into arguing with the referee and wrangling with their opponents, failed to build on that and fell behind again in the 68th minute.
Zapata tripped Ranegia, picking up his second yellow card in three minutes, and 35-year-old Di Natale converted from the spot.
Milan's hopes of fighting back ended when Boateng was booked for fouls on Giampiero Pinzi and Roberto Pereyra and was also dismissed in the 83rd minute, the low point in yet another inept display by the visitors.