Messi is the favourite to win a record-breaking sixth Ballon d’Or in Paris on Monday and he came up trumps again for Barca at the Wanda Metropolitano, where an even contest looked destined to finish goalless.
“In matches that are close and intense, having Leo is always a big advantage,” said Barcelona coach Ernesto Valverde.
The Argentinian’s 86th-minute strike, after a neat one-two with Luis Suarez, keeps Barcelona level on points with Real Madrid at the top of the table while leaving Atletico with a mountain to climb if they are to rejoin the race.
“It’s important for the three points but also for the mental side,” said Valverde.
“It sends us into the Christmas period with confidence.”
Atletico now sit six points adrift of both Real and Barca, with those two also having a game in hand which will be played out in the season’s first Clasico at the Camp Nou on Dec 18.
It means Atleti could conceivably head into the Christmas break nine points off the lead, a significant gap, particularly considering they will have to play away against both Barca and Real Madrid in the second half of the season.
“We need points,” said Atletico coach Diego Simeone.
“We are not far from them but we are worried. I am happy with the way we are playing but I will not smile at that because that does not bring us points.”
But Messi scored his 12th goal of the season and sixth in his last five games. He has now 25 in 27 in the league against Atletico although this was his first at the Wanda Metropolitano.