It is understood that Sainz had a Richard Mille watch - the Alexander Zverev model named after the German tennis player worth £235,000 - taken as he left the Armani Hotel on Viale Manzoni.
Three people, who are thought to have been waiting outside the hotel for some time, encountered Sainz and stole his watch.
The F1 driver then set off in pursuit with his personal trainer, while bystanders who had seen the robbery also attempted to help intervene.
Sainz and his assistant managed to stop one of the three robbers after a car, then foot, chase.
The second robber was then stopped on Via della Spiga by Sainz’s manager.
The third was stopped very shortly after with the help of another one of Sainz’s personnel.
Police officers then arrived on the scene and took the robbers, aged between 18 and 20, into custody.
Sainz retrieved the Ferrari team sponsor watch before returning to his hotel.
Source: Autosport