Roma 4 – 0 Fiorentina
The capital club have won their last 14 home games in Serie A, breaking their record which had stood since 1930.
Dzeko, who is now the league’s top scorer with 17 goals, opened the scoring before Federico Fazio headed in a second.
Radja Nainggolan turned in Kevin Strootman’s cross and Dzeko capitalised on a Davide Astori error to complete the comfortable victory.
Roma, who move up to second, are four points behind leaders Juventus, although they have played a game more than the champions.