Inter scored three goals in the last seven minutes to seal an incredible 3-2 win over Sampdoria yesterday and extend their unbeaten run to 18 Serie A games.
Leaders Juventus beat Livorno 4-2 at the Delle Alpi stadium with two goals from Italy winger Mauro Camoranesi and they now have a four-point lead over Milan who were held by Palermo in the evening match in Sicily.
Third-placed Udinese beat Cagliari 2-0, Paolo Di Canio's rich vein of form continued with a goal in Lazio's 3-2 win at Fiorentina, and Vincenzo Montella scored both Roma's goals in their 2-1 victory over Atalanta.
Fourth-placed Inter were trailing 2-0 to Sampdoria after goals from Max Tonetto and Belarussian Vitali Kutuzov.
Roberto Mancini's side then struck three times in six minutes through Nigerian Obafemi Martins, Christian Vieri and Uruguayan Alvaro Recoba whose superb winner came in the fourth minute of stoppage time.
Many Inter fans had left the San Siro after Kutuzov's goal in the 82nd minute and missed seeing their team turn the game around in the dying minutes.
After Tonetto had put Samp ahead against the run of play a minute before the break, Inter had a series of chances to draw level but with Brazilian Adriano off-form they could not break through.
After the frustration came what looked to be the killer blow when Kutuzov, on loan from Milan, finished off a perfectly executed counter-attack.
Substitute Martins started the fightback in the 88th minute, firing home with the outside of his left foot and a minute into stoppage time Martins set up Vieri who volleyed the equaliser.
Inter piled forward in search of a winner and it came with a sweetly struck drive from Recoba that left Sampdoria stunned.
Inter are fourth in the standings but are still 13 points behind leaders Juventus, who returned to winning ways after two successive draws.
A 17th-minute header from Alessandro Del Piero put Juve on their way and Camoranesi made it 2-0 eight minutes later with a tap-in after Zlatan Ibrahimovic had headed against the bar.
Portuguese midfielder Jose Vidigal headed Livorno back into the game just before the break but Ibrahimovic restored the two-goal cushion in the 75th minute with a fine drive following a smart move.
Matteo Melara pulled one back for Livorno but a Camoranesi penalty ensured the points for Fabio Capello's side.
Milan lacked cohesion up front for most of the match against a spirited Palermo and had goalkeeper Dida to thank after a superb save late in the first half on Palermo's Morrone.
Milan had cut the gap on Juventus to two points after a series of fine showings including 11 goals in their last two home games and an away draw at Juventus before the Christmas break.