BERGAMO - Inter crashed to a 3-1 defeat at local rivals Atalanta on Sunday but remain on top of the Serie A table at the midway point in the season.
Sergio Floccari opened the scoring on 18 minutes and Cristiano Doni added a quick double to give Del Neri's side a healthy lead inside the 33rd.
Zlatan Ibrahimovic grabbed a consolation goal in added time at the end of the second half but it was too little, too late for José Mourinho's side.
The Portuguese coach was forced to make a change in defence in the hours leading up to the Week 18 clash in Bergamo, with Samuel returning to Milan late morning after going down with the flu. In came Burdisso at the centre of defence, with Crespo making his first Serie A start of the season in attack and Stankovic returning in the playmaker role after a two-game absence.
Atalanta came out firing on all cylinders and Doni went close early on with a shot on the turn. Seconds later Floccari narrowly missed after being picked out by Guarente but hit the target soon after when he swivelled in the box and beat Julio Cesar with a crisp finish.
Valdes and Floccari had more chances for Atalanta before Doni doubled their lead with a free kick that flew in off Ibrahimovic.
Mourinho threw on Obinna in place of Chivu but Atalanta scored a third before the Nigerian could make an impact, Doni rising in the area to head home a splendid inswinging cross from Valdes.
A touch of nervousness crept in at the break with Rizzoli showing Ibrahimovic a yellow card that rules the Swede out of next Sunday evening's visit of Sampdoria.
Mourinho used up his remaining two substitutions at half time, bringing on Luis Figo for Maxwell and Adriano for Hernan Crespo.
Inter made an enouraging start to the second period with Adriano's overhead kick from Obinna's cross going just over Coppola's bar. But Atalanta quickly settled back into their first-half rhythm and Ferreira Pinto tested Julio Cesar before Guarente fired into the sidenetting.
Substitute De Ascentis went even closer on 56 minutes, his follow-up coming back off the post after a Julio Cesar parry from Ferreira Pinto's low drive.
Adriano and Ibrahimovic had shots saved by Coppola, Obinna blasted high and wide from an inviting position and was denied by the Atalanta keeper in the closing minutes before the Swede popped up in added time to slot home from close range a headed assist from Adriano.
Atalanta 3-1 Inter (HT: 3-0)
Scorers: Floccari 18, Doni 28, 33, Ibrahimovic 90+2.
Atalanta: 31 Coppola; 8 Garics, 2 Talamonti, 5 Manfredini, 6 Bellini (16 Rivalta 85); 79 Ferreira Pinto, 17 Guarente, 20 Valdes (15 De Ascentis 50), 22 Padoin; 33 Floccari (32 Vieri 90), 72 Doni.
Subs not used: 1 Consigli, 13 Peluso, 27 Capelli, 34 Defendi.
Coach: Luigi Del Neri.
Inter: 12 Julio Cesar; 13 Maicon, 2 Cordoba, 16 Burdisso, 6 Maxwell (7 Figo 46); 4 Zanetti, 19 Cambiasso, 26 Chivu (21 Obinna 29); 5 Stankovic; 8 Ibrahimovic, 18 Crespo (10 Adriano 46).
Subs not used: 1 Toldo, 9 Cruz, 11 Jimenez, 24 Rivas.
Coach: José Mourinho.
Referee: Nicola Rizzoli (Bologna).
Booked: Burdisso 36, Ibrahimovic 45+2, Bellini 67, Vieri 90+1.