Barcelona will win La Liga on Wednesday if Atletico Madrid loses to Valencia after a 2-0 victory over Alaves gave them a 12-point lead at the top of the table.

Lionel Messi started on the bench at Mendizorrotza on Tuesday in a move that made clear just how comfortable Barca are in this title race, its conclusion surely now only a matter of when rather than if.

Should Atletico avoid defeat to Valencia at the Wanda Metropolitano, the Catalans will still be crowned champions on Saturday at the Camp Nou with a victory over Levante.

They could even have it wrapped up before kick-off on Saturday if Atletico fails to take at least four points from Valencia and Real Valladolid, the latter whom they face a few hours earlier on Saturday.

"It's an incredibly valuable win," coach Ernesto Valverde said. "In the end however much as people say the league is won, it has to be achieved on the field.

"We are at the gates now, needing three points more with four games ahead. It is an immense joy to be in this position after so many months of work."

Real Madrid, who play their game in hand against Getafe on Thursday, sit 16 points adrift in third. Alaves stay eighth, their hopes of a Europa League spot fading fast.

Messi came on as a substitute in the 61st minute shortly after his team had scored twice, Carles Alena guiding one into the corner before Luis Suarez, in Messi's absence, took and dispatched a penalty.

Valverde leaving out his captain and star player, presumably with an eye on next week's Champions League semi-final against Liverpool, was a luxury Barcelona have earned and can afford.

Liverpool, still jostling with Manchester City in the Premier League, are unlikely to feel the same sort of confidence when they face Huddersfield on Friday.

"The idea at half-time was to play Leo because the result was not clear," Valverde said. "But regarding the Golden Boot and that sort of thing, we are only focused on what we have to do to win.

"Leo has a lot of individual challenges ahead, but today it was time to rest." 

Other players were preserved too. Jordi Alba, Clement Lenglet and Arthur Melo all began on the bench, allowing Samuel Umtiti more minutes as he recovers from a knee injury, while the struggling Philippe Coutinho started in a front three with Ousmane Dembele and Suarez.

Alena, the 21-year-old Spaniard, scored his second La Liga goal and showed again why many believe he could be a key figure for Barcelona in the years to come.