MILAN, Italy -- Inter Milan's run of poor form continued as Catania came from behind to beat Claudio Ranieri's side 2-1 in Serie A on Saturday.
The result leaves Inter, which has one win from six games, languishing just outside the relegation zone, while Catania moved into sixth ahead of the weekend's remaining games.
There was better news for AC Milan, which stormed to a 3-0 victory at home to Palermo. Parma won 2-1 at Napoli in the day's other game.
Esteban Cambiasso gave Inter the perfect start when he volleyed in Maicon's cross after six minutes. That seemed to spark Catania into life but it could not find a way past a solid Inter defence.
The match was turned on its head in five second-half minutes. Catania got back on level terms almost immediately after the restart when Gonzalo Bergessio raced from just inside his own half and slotted the ball to Sergio Almiron, who lifted it over Inter goalkeeper Luca Castellazzi from the edge of the area.
Things went from bad to worse for Inter in the 50th minute when Castellazzi was adjudged to have brought down Bergessio and Francesco Lodi fired home the resulting penalty to give Catania the lead.
Inter tried to find a way back into the game but without success and it was Catania who went closest to scoring when, in the 82nd minute, Andrea Catellani raced clear on the counterattack, but Castellazzi got down well to divert the danger.
Cambiasso almost rescued a point for Inter in injury time, but the ball was scrambled clear by the Inter defence as the Argentina midfielder was about to strike.
"No one among us is happy," Ranieri said. "But we want to react and get back on top.
"I don't know how much of a penalty it was and how much the Catania player was already on his way down. But it could have been that the referee gave the penalty because it was difficult to see. And even if he made a mistake, it doesn't change anything because he controlled the game well."
Milan moved the right way up the table with a comfortable win at the San Siro.
Massimiliano Allegri's team was in control from start to finish and deservedly took the lead five minutes before halftime.
Alberto Aquilani nodded down Zlatan Ibrahimovic's cross to Antonio Nocerino for the former Palermo player -- who joined Milan an hour before the transfer window shut in the summer -- to score his first Milan goal.
Ibrahimovic was again on hand in the 55th minute to slot a brilliant through ball for Robinho to race onto and stroke home.
Antonio Cassano capped a perfect night for Milan in the 64th minute when Ignazio Abate picked him out unmarked with a deep cross which the striker headed in for his side's third of the night.
Elsewhere, Napoli missed the chance to go top in a disappointing night at the Stadio San Paolo.
Parma took the lead shortly before the hour mark when Sergio Floccari backheeled the ball into the path of Massimo Gobbi, who fired it into the bottom right corner.
The home players thought they had rescued a point when Giuseppe Mascara latched onto Ezequiel Lavezzi's backheel and levelled matters in the 76th minute.
But, eight minutes from time, Sebastian Giovinco sent a powerful pass across the face of goal for the simplest of tap-ins for Francesco Modesto.
Inter, Milan and Napoli are all in Champions League action this week. Inter is away at Lille Tuesday, when Napoli entertains Bayern Munich. Milan hosts BATE Borisov Wednesday.