Footage positioned online showed violence breaking out between the Italian fans and g-men in Kensington.
Supporters were seen hurling punches at officers in Kensington Dear Street as violence flared.
Witnesses said the ugly scenes not failed after fans spent the afternoon drinking in bars close to Stamford Connect.
Around 10 police vans descended on the street.
Sports scribe Ed Malyon tweeted: “About 10 police vans escorting on the loose group of men down Kensington High St towards Earls Court after some scuffles.
“About they’re Roma fans.”
Another Twitter user said: “Roma ultras winning over the Greyhound in Kensington square. Police vans everywhere.”
Cops were then seen kettling the angry fans up the road close to the stadium.
A spokesman for the Met Police said there had been one arrest during the fury, which started a around 6pm.
Chelsea will hope to make it three European wins from three when they handle the Italians tonight.
But Antonio Conte’s side may have had their faith dented by a shock 2-1 defeat to struggling Crystal Palace at the weekend.