Cliftonville suffered a heavy 8-1 defeat against Benfica in their Women's Champions League debut on Wednesday.
Lara Martins and Lucia Alves both netted twice, with Marie Alidou, Andrea Sanchez and Beatriz Nogueira also getting on the scoresheet. Rachel Norney scored an own goal.
Caitlin McGuinness scored the Red's first ever European goal with a second-half header.
Benfica will now face SFK Riga in the next round on Saturday.
Benfica were fast out of the blocks in Lisbon, with Norney called into action after only four minutes, pushing away Alidou's effort.
She would make another sprawling save to deny the same player three minutes later, before the Reds' best chance of the game arrived.
Toni-Leigh Finnegan headed wide from inside the area after the second phase of a free-kick fell kindly to her in the area.
The home side remained in control and broke Cliftonville's resolve on 25 minutes as Alidou was not to be denied a third time.
The Canadian midfielder met Sanchez's pin-point delivery and produced a powerful header which flew past Norney and into the top corner.
Benfica would double their advantage in fortuitous circumstances on 34 minutes, when, after Norney thwarted Alidou and she saw a shot cleared off the line, an unfortunate clearance hit the goalkeeper and trickled over the line.
Another goal two minutes later would further stretch the Portuguese side's lead, with Alves sweeping home after meeting Andreia Faria's low cross.
Sanchez would go from provider to goal scorer when she netted in the 42nd minute with a glancing header from Nycole Raysla's free-kick.
Benfica picked up where they left off after the break, with substitute Lara Martins scoring four minutes after the restart.
The striker had the easiest of tap-ins after being found in the box by Sanchez.
Her second and Benfica's sixth was the pick of the goals, as she produced a fine rabona finish into the bottom corner from inside the box.
Despite the score line, the Reds continued to push forward, with Kirsty McGuinness forcing Lena Pauels to tip her rasping strike from range over the crossbar.
Her sister Caitlin McGuinness would make history from the resulting corner, rising highest to meet Finnegan's delivery and heading into the top corner.
Benfica remained in control however, as Alves got her second of the game on 73 minutes. She weaved her way past Fi Morgan, before coolly slotting past Norney.
Nogueira rounded off the scoring three minutes later, with a close range header after Andreia Norton stood the ball up for her.
They will now face BIIK Kazygurt of Kazakhstan on Saturday in their final Group 6 game, with Kazygurt having lost against Riga in their tie.