Jurgen Klopp’s men will bid to win their first piece of silverware since the Premier League title in 2020.
The tie was finely poised after a goalless first leg at Anfield last week.
Arsenal put Liverpool under early pressure, with Caoimhin Kelleher making a fine save from Alexander Lacazette’s free-kick.
And the Reds then took advantage to open the scoring through a fine Diogo Jota goal in the 19th minute.
The visitors should have doubled their lead early in the second half when Kaide Gordon blazed over the bar before Ibrahima Konate cannoned a header off the post.
But Liverpool wrapped up the victory in the 77th minute - and it was that man Jota again.
He latched on to an outstanding through ball from Trent Alexander-Arnold and calmly dinked over Gunners keeper Aaron Ramsdale.
Jota was initially flagged offside but a VAR check overruled the decision and the goal stood.
Any chance of Arsenal comeback was over when Thomas Partey was sent off in the 90th minute.
- Diogo Jota: what a performance and what a season the Portuguese is having. Jota’s goals either side of half-time were of top-class quality. In a night that Liverpool’s key players need to step up, he did just that.
- Trent Alexander-Arnold: had a good battle with Gabriel Martinelli in the first half. The Liverpool right-back was tested but came through things. Then he underlined the influence he has attacking-wise with two assists. The second really was a pass that only a handful of players in the world possess.
- Caoimhin Kelleher: it was a brave call from Klopp to start the Republic of Ireland international rather than Alisson Becker in goal. But Kelleher made a big save from Lacazette early on that could have changed the whole game had it gone in.
- Aaron Ramsdale: the Arsenal keeper will be left disappointed he couldn’t stop Jota’s first goal. It was a scruffy finish from the Liverpool striker yet Ramsdale was unable to get down to the effort.
- Ben White: given the runaround by Jota all night. Was left for dead early in the second half and Gordon should have scored from just 10 yards. Then White lost the run of Jota when he wrapped up the game.
- Mikel Arteta: had plenty of attacking players on the pitch - yet Arsenal created a dearth of goalscoring chances. Arteta failed to find the solutions and his troops instead went out with a whimper.
Arsenal: Ramsdale 4, Tomyasu 4, White 4, Gabriel 5, Tierney 5, Lokonga 5, Odegaard 5, Saka 5, Smith Rowe 5 (Partey 74; 3), Martinelli 6, Lacazette 5 (Nketiah 74; 5)
Liverpool: Kelleher 7, Alexander-Arnold 8, Matip 5 (Konate 46; 7), Van Dijk 7, Robertson 8, Fabinho 8, Henderson 6 (Milner 75; 6, Jones 7, Gordon 6 (Minamino 63), Firmino 7 (Williams 85), Jota 9.
What’s Liverpool’s next fixture?
The Reds turn their attention back to the Premier League when they travel to Crystal Palace on Sunday (14.00).
Arsenal, meanwhile, host Burnley at the Emirates (14.00).