Malcom struck shortly before the hour mark to cancel out Lucas Vazquez's early goal and earn Barcelona a 1-1 draw with Real Madrid in Wednesday evening's Copa del Rey semi-final first leg at Camp Nou.
Los Blancos enjoyed the better of things in the first half and took a lead into the break thanks to Vazquez's close-range finish early on, assisted by in-form striker Karim Benzema.
Barca, minus star man Lionel Messi for the opening hour, struggled to get going for large parts of the match but they managed to find a way through thanks to Malcom's goal, leaving the tie wide open ahead of the return match in three weeks' time.
A little over three months on from their humiliating 5-1 loss here that cost Julen Lopetegui his job, Madrid took all of seven minutes to show that they are a far more settled side now under Santiago Solari.
Marc-Andre ter Stegen had already parried a long-ranger from Toni Kroos by the time that Vazquez opened the scoring from a few yards out, profiting from some good play from Benzema to play the ball into his path from the byline.
Madrid had chances to double their tally against a Barca side that took time to get going, but Benzema and Vinicius Junior got in each other's way when it was three against two, before the latter dragged an effort wide from a good position five minutes later.
Barcelona's first signs of revival came shortly before the half-hour mark as Malcom was played onside by Marcelo - despite the linesman later raising his flag - and had just Keylor Navas to beat, but he could not get the better of Madrid's deputy keeper.
Kroos and Gerard Pique both came close in an end-to-end half in Catalonia, while Luis Suarez had a shot pushed to safety by Navas after being teed up by the lively Malcom, who was asked to fill in for the half-fit Messi.
Despite the visitors looking the more dangerous in the final third, it was the holders who came closest to a second goal in the first half as Ivan Rakitic glanced a free kick against the crossbar.
A wayward Philippe Coutinho shot aside, which Navas watched sail over his bar, Barca offered little in the 12 minutes leading up to their equaliser.
Navas took a risk by racing off his line and could not clear the ball, allowing Suarez to hit the post from a narrow angle, with the loose ball being pounced on by Malcom to squeeze it home.
The calls from the stands for Messi to be introduced became deafening as Barca toiled and Ernesto Valverde obliged by bringing on the superstar forward.
Messi's only real involvement in the match was to send a free kick into the wall, as Barca struggled to push on from their leveller.
Fellow substitute Gareth Bale had a great chance to win the game in the final 10 minutes, but he required a couple of touches to set himself after Ter Stegen raced off his line to half-clear the ball and the Welshman could not get a clean shot on the unguarded net.
Barcelona, who have won this competition four seasons running, travel to the Spanish capital for the return leg on February 27.
BARCELONA (4-3-3): Ter Stegen; Semedo, Pique, Lenglet, Alba; Rakitic (Vidal 63'), Busquets, Arthur; Malcom (Alena 76'), Suarez, Coutinho (Messi 63')
REAL MADRID (4-3-3): Navas; Carvajal, Varane, Ramos, Marcelo; Kroos, Llorente (Casemiro 63'), Modric; Vazquez (Asensio 84'), Benzema, Vinicius (Bale 64')