FLORENCE - Fiorentina stretched their unbeaten home run to nineteen matches and Inter lost the top spot as Wednesday's Serie A clash at the Artemio Franchi ended goalless.
Mourinho's Nerazzurri made a strong start and were unlucky not to take a 5th-minute lead when Mancini's angled drive crashed on to Frey's crossbar after a cheeky through ball from Ibrahimovic.
Spurred on by a full house in Florence, the Viola attacked back and Pazzini forced Julio Cesar into a save with a flicked header from Santana's cross.
Ibrahimovic looked good for his sixth of the Serie A season on 27 minutes but the Swede hooked wide from a tight angle after collecting Mancini's lofted pass.
Osvaldo had heaps of chances as Fiorentina found acres of space on the right flank, his best chance coming just before the half hour when he powered over a header from Kuzmanovic's strong cross.
Julio Cesar was called into action again before the break with a great save from Pasqual's scorching free kick.
Mourinho made changes 17 minutes after the restart, replacing Obinna and Mancini with Crespo and Vieira. The Argentine forward almost made an immediate impact minutes after coming on when he had a shot parried by Frey.
Prandelli's reply was to introduce Almiron for Kuzmanovic and replace the tiring Osvaldo with Jovetic.
Fiorentina created three good chances for a late winner. Gamberini climbed highest to head over a Montolivo corner. Pazzini then powered over his header after Pasqual's half-volleyed cross from the left.
And Jovetic fired narrowly over as the Viola maintained their search for a fifth consecutive victory until the final whistle.
Fiorentina 0-0 Inter
Fiorentina: 1 Frey; 21 Comotto, 5 Gamberini, 2 Kroldrup, 23 Pasqual (14 Zauri 87); 22 Kuzmanovic (30 Almiron 69), 88 Felipe Melo, 18 Montolivo; 24 Santana; 29 Pazzini, 9 Osvaldo (8 Jovetic 74).
Subs not used: 13 Storari, 4 Donadel, 7 Semioli, 54 Da Costa.
Coach: Cesare Prandelli.
Inter: 12 Julio Cesar; 13 Maicon, 2 Cordoba, 16 Burdisso, 6 Maxwell; 4 Zanetti, 5 Stankovic (77 Quaresma 82), 26 Chivu; 21 Obinna (18 Crespo 62), 8 Ibrahimovic, 33 Mancini (14 Vieira 62).
Subs not used: 1 Toldo, 15 Dacourt, 23 Materazzi, 45 Balotelli.
Coach: José Mourinho.
Referee: Roberto Rosetti (Turin).
Booked: Kroldrup 53, Maicon 60.