Roma secured third place thanks to a bizarre Gianluca Pegolo own goal from the attempted Kostas Manolas cross.
The Giallorossi were already in the Champions League, but wanted one last push to secure third ahead of their city rivals Lazio. Radja Nainggolan was suspended with Alisson Becker, Gregoire Defrel and Bruno Peres injured. The Neroverdi were coming off a surprise win away to Inter, but missed Pol Lirola and Edoardo Goldaniga.
Patrik Schick burst down the right for a right-foot finish that smacked against the upright after 14 minutes.
Edin Dzeko saw his towering header skim the crossbar, but Matteo Politano had penalty appeals waved away for a shot charged down by the hand of Maxime Gonalons.
Gianluca Pegolo flew to palm a Dzeko curler away, although at the other end Lukasz Skorupski in his first Serie A appearance of the season made a stunning low reaction save one-handed on Politano and the Italian off balance turned the rebound over.
Roma took the lead almost by accident on the stroke of half-time. Kostas Manolas ran to the by-line and attempted a taut cross at the near post, but it bounced off Pegolo and into the net.
There was bad news for Sassuolo after the restart, as Federico Peluso landed very awkwardly and had to be stretchered off with suspected knee ligament damage.
Skorupski denied Domenico Berardi one-on-one, even though the forward was offside, and Aleksandar Kolarov performed a magnificent tackle to stop Khouma Babacar dead as he was clear on goal.
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