AC Milan produced an outstanding away display in Rome to defeat Roma and boost their slim hopes of a top four finish, whilst denting Roma's in the process.
Roma boss Eusebio Di Francesco made a big call with his team selection, dropping top scorer Edin Dzeko in favour of Patrik Schick. The game started off very slow, with both teams making sloppy errors as neither side showed any real quality in the final third.
The hosts had a couple of half chances, Czech forward Schick's volley brought a save from Gianluigi Donnarumma but the offside flag had gone up. Midfielder Lorenzo Pellegrini then tried his luck from range but his shot failed to test Milan keeper Donnarumma in a dull first half which was very much being decided by the two resolute defences.
The second half got off to much livelier start, and Milan stunned the Stadio Olimpico when Patrick Cutrone latched on to Suso's cross and tucked home under Allison to give the visitors a lead with their first real chance of the game.
The goal seemed to leave Roma stunned, as the hosts failed to play their usual slick football and communication seemed to be all over the place, whilst Gennaro Gattuso's Milan continued their assured performance and almost doubled their lead when Franck Kessie's drive was well saved by Allison.
Out of form Radja Nainggolan came off for Edin Dzeko as Roma turned to their star man to partner the goalless Schick as a front two with 25 minutes left. Giallorossi boss Di Francesco had previously said the two up front together didn't work, and they did little to prove critics wrong after looking isolated throughout.
Milan continued to catch their hosts on the break, almost doubling their lead when a superb counter saw centre back Alessio Romagnoli follow up on an Allison save but a brilliant challenge from Kevin Manolas denied him. It was 2-0 around 90 seconds later, as a superb one-two saw ex-Blackburn forward Nikola Kalinic play in full-back Davide Calabria.
The defender proceeded to calmly dink Allison to finish off an outstanding piece of play and leave the hosts well and truly stunned as they continued to dominate Roma in the Italian capital. The home side's shocking performance was summed up when usual dead ball expert Aleksandar Kolarov blasted a promising free-kick into the wall as the home fans grew restless with every passing minute.
Milan should have made it worse for Roma, but ex-Liverpool forward Fabio Borini somehow blasted over from around six yards out after getting on the end of Hakan Calhanoglu's low cross.
With third placed Lazio and fourth placed Inter both winning earlier in the weekend, Roma knew the importance of a win to keep the pressure on their rivals, but the questionable decision to drop free scoring Dzeko and the dreadful performance of the home side will not do much for critics of manager Di Francesco. Home fans certainly made their feelings known, filling the Stadio Olimpico with deafening boos at full time.
As for Milan, the win, their first away to Roma since October 2011, pulls them to within six points of their opponents and leaves them with a slim chance of a top four finish, with a derby against Inter to come at the weekend. The brilliant display from Gennaro Gattuso's side will not have made good viewing for Arsene Wenger, whose Arsenal side face the Italians in the last 16 of the Europa League on the 8th and 15th March.
The Gunners were extremely poor as they lost 3-0 to Manchester City in the Carabao Cup final earlier in the day, and the limp manor of their attack and defence coupled with Milan's drastic improvement all over the pitch will leave Gattuso's side with real confidence ahead of the Londoner's trip to the San Siro.