Barcelona captain Lionel Messi scored a brace that put his side on the verge of the Champions League final then backed Philippe Coutinho after the ex-Liverpool midfielder's underwhelming display against his old club prompted jeers at Camp Nou.

The Blaugrana beat Jurgen Klopp's Liverpool 3-0 in the first leg of their semi-final on Wednesday, with Messi netting his 599th and 600th goals for the club after Luis Suarez had broken the deadlock in the opening period.

While Suarez made a meaningful impact against his former team with his first Champions League goal in over a year, Coutinho was once again largely anonymous before being substituted on the hour mark when Liverpool were on top.

The Brazil international has struggled in his first full year at Barcelona, yet he received support from Messi after the game.

"We are in a defining moment and it is not time to criticize anyone," Messi told Movistar Plus.

"It is time to make everything happen as we talked at the beginning of the season. It is ugly to see a team-mate get booed like that.

"We must all be together and support."