The Brazilian broke the deadlock shortly after arriving from the bench, and Valverde spoke about the 21-year-old after the game.
“It was a great game. Our primary target was to qualify. We played well in every aspect,” he said.
“We pressed well, we attacked well, all that was missing was a little bit more accuracy over the final metres.
“And we’re all so happy for Malcom. He had the finish that we had been missing at other times in the game.
“He has been working hard to get better every day. He’s still young and there’s a lot of margin for improvement.”
Barcelona were without Lionel Messi once again, despite the captain having travelled with the squad to Milan, and Valverde offered an update after the game.
“We wanted the whole team to travel to train together, but in the end it was not the same training as the calibre of this match, with that intensity,” he said.
”The decision has been simple: we preferred not to take risks. We’ve talked to him and he’s been clear.”
Barcelona have just one more game now before the international break, at home to Real Betis on Sunday, it remains to be seen if Messi will make his comeback in that game.