Malcom scored for Barcelona against Roma, whom he had snubbed the previous week, but it was not enough to prevent defeat for the Catalan giants.
The 21-year-old Brazilian had been announced by the Serie A side before eleventh hour negotiations from Barca sealed a €41m move last week.
Roma had joked, via their Twitter account, ahead of the match that they would be ‘muting’ all words in relation to the winger.
Malcom gave Barca a 2-1 lead after Stephan El Shaarawy had cancelled out Rafinha Alcantara's sixth-minute opener for Ernesto Valverde’s side.
However, late goals from Alessandro Florenzi, Bryan Cristante and Diego Perotti ensured the Italian side picked up the victory against the side whom they had eliminated from Europe three months earlier.