Juergen Klopp puts all his focus in the league
The Reds have 40 points, 11 points clear of Manchester City, while Brighton have 15 points.
The first half went further towards Brighton, where Van Dijk opened the scoring with a free kick from Arnold, the Dutchman lifting the ball into the net and Sadio Mane missing another chance.
In a repetitive scenario, Arnold played a corner, which Van Dijk headed in the net, shaking the visitors' spirits.
Liverpool beat Brighton (2-1) in an exciting match on Sunday at Anfield, in the 14th round of the Premier League.
Liverpool scored two goals for Virgil van Dyck in the 18th and 24th minute, while Lewis Dunk pulled one back for Brighton in the 79th minute.
The visitors were relatively active in the second half, hoping to reduce the gap with Louis Dunk's shot and a header from striker Aaron Connolly.
Leverkusen coach Juergen Klopp felt that the game was guaranteed, and began to rest his stars since the 69th minute, with the departure of Mohamed Salah and the participation of Adam Lallana, and then replaced Devok Origi substitute for Roberto Firmino.
However, Brazilian goalkeeper Alison Baker made a foolish mistake in the 77th minute when he saved a handball outside the penalty area and Klopp lost his third substitute, having to replace substitute goalkeeper Adrian in Chamberlain's place.
Brighton tried to threaten Lever with his right-back Martin Montoya and a shot from defender Louis Dunk over the bar.
However, Chamberlain almost scored a third goal, after a quick attack started by Mani and passed to Firmino, and then to Salah, who paved the ball for Chamberlain, to hit the final in the arms of Matthew Ryan, goalkeeper Brighton.