ROME, Nov 5 (Reuters) - AC Milan slumped to a third defeat in four Serie A matches when they lost 2-0 at Atalanta after second-half goals by Nicola Ventola and Andrea Soncin on Sunday.
The result left Milan 16th in the 20-team division with seven points from 10 matches, 17 points behind joint leaders Inter Milan and Palermo, who enjoyed 2-0 victories over Ascoli and Sampdoria respectively.
AS Roma stayed third on 20 points after coming from behind to beat visitors Fiorentina 3-1.
Milan travelled to Atalanta fresh from a 4-1 win over Champions League rivals Anderlecht and were hopeful of getting their league challenge back on track after recent losses to Inter and Palermo.
Their failure to capitalise on good first-half possession was punished, however, in the 50th minute, when home keeper Alex Calderoni pumped the ball upfield for Massimo Donati to nod on to Ventola, who volleyed crisply past Dida.
Calderoni pulled off a fingertip save to keep out an Andrea Pirlo free kick and as Milan's frustration grew Joann Gourcuff was booked for diving.
Atalanta made sure of the points in the second minute of stoppage time, when Soncin's shot deflected off Dario Simic into the net.
Milan coach Carlo Ancelotti accused referee Tiziano Pieri of failing to spot two penalties for what he said were fouls against winger Daniele Bonera and Gourcuff.
'I'm very angry because this is the third or fourth time this season that this has happened to us,' Ancelotti told Italy's SKY television.
'I don't know if the referees have got it in for Milan. I like to think these things happen by chance. But they are happening to us with increasing frequency.'
Milan's city rivals Inter had few problems overcoming Ascoli, who have yet to win in Serie A this season.
Zlatan Ibrahimovic created their opening goal just before halftime, when he dribbled into the area and cut the ball back to Hernan Crespo.
The Argentine striker scuffed a weak shot goalwards but Inter captain Javier Zanetti was ready just inside the box to make sure it crossed the line.
Eight minutes after the restart, Ascoli defender Mirko Cudini turned Luis Figo's low cross into his own net to extend Inter's lead. Inter goalkeeper Julio Cesar preserved his side's two-goal cushion with a penalty save after Douglas Maicon handballed.
Palermo made up for their midweek defeat to UEFA Cup rivals Newcastle United with a comfortable home victory over Sampdoria - their fourth Serie A win in a row.
Eugenio Corini curled a free kick past visiting keeper Luca Castellazzi in the 35th minute.
Italy defender Cristian Zaccardo wrapped up the win midway through the second half by poking in the loose ball after Castellazzi had spilled a shot by Giuseppe Biava.
In the late match at Rome's Olympic Stadium, Czech defender Tomas Ujfalusi gave Fiorentina the lead with a goal in the 15th minute, only for Italy midfielder Daniele De Rossi to rifle in a superb long-range equaliser just before halftime.
Roma were much the better side after the break, however, and Brazilian playmaker Rodrigo Taddei netted twice from close range to wrap up the victory.