Ernesto Valverde knows his Barcelona side have room for improvement despite ending 2018 with a 2-0 win over Celta Vigo that keeps them three points clear at the top of LaLiga.

First-half goals from Ousmane Dembele and Lionel Messi sealed Barca's latest victory at Camp Nou and restored their cushion over Atletico Madrid, who had won earlier on Saturday.

"It was the objective to end the year as leaders, with the same advantage as we had before this round of matches started, so we are happy," Valverde was quoted as saying by his club's official website.

However, the coach recognised his side were below their best in an underwhelming second-half showing that saw Celta have 55 per cent possession, albeit without seriously threatening to pull off a comeback.

"What most satisfies me is to have dominated the first half and generated chances," Valverde told a news conference.

"If you concede zero goals, it's the easiest way to win. But it's not our goal. Our goal is to generate danger."

Valverde had words of praise for Dembele, stating: "He is a player who is scoring goals, playing, working. We expect a lot from him. We hope he keeps making good decisions." 

He also confirmed his players would be given a week off over Christmas, returning to training on December 30, before their LaLiga campaign resumes on January 6 with a trip to Getafe.