There were mitigating circumstances in Samp's defeat - they lost goalkeeper Fabrizio Ferron with an injury in the first half and they had two men, Sinisa Mihajlovic and Emanuele Pesaresi, sent off in the second half.
The win puts the former champions Milan 11th in the table with eight points. Internazionale and Juventus are the only unbeaten teams. Inter beat Parma 1-0 on Saturday with a spectacular free-kick by Ronaldo while Juventus, two points behind them, routed Udinese 4-1.
However, Udinese are appealing for the match to replayed after television pictures showed that Oliver Bierhoff's 50th minute shot had crossed the line rather than been cleared by Ciro Ferrara. The score was 1-1 at the time.
Apparently they have a strong case, as a Udinese official, Giampaolo Pozzo said: "The regulations are clear - if the referee admits his mistake, the match has to be played again," he said. "I have faith in the footballing authorities."
Lazio won the the Rome derby 3-1 despite being reduced to 10 men for all but three minutes of the game after Giuseppe Favalli was sent off.
Barcelona stunned their great rivals Real Madrid with an unscheduled 3-2 victory in the Bernabeu stadium on Saturday and are now seven points clear in the Spanish League. Real are third.
Barca's two Brazilians, Rivaldo and Giovanni, scored the first and last goals in a match which they fought largely from a defensive position. In ending Real's unbeaten run the Catalan club extended their own to nine games.
Benfica's new coach, Graeme Souness, saw his new club win away for the first time this season, beating Chaves 1-0. It leaves them eight points behind the defending champions, Porto.
Bayern Munich trailed twice and had Samuel Kuffour sent off but still managed to draw their Bundesliga derby with 1860 Munich 2-2. The German champions are four points behind Kaiserslautern who also drew 2-2, at Borussia Dortmund on Friday.
Mexico qualified for next year's World Cup finals in France despite being held to a 0-0 draw by the United States in their CONCACAF zone qualifying match yesterday.Reuse content