"Of course we can win (the title)," Koeman said at his post-match press conference.

"If we improve and we have more confidence and we improve our effectiveness (in front of goal), there's a chance.

"There are still lots of games left remaining. We know our situation in the league

"We knew after we lost against Cadiz we had to win and let's hope that is good for the confidence."

Messi's winner, a crisp shot off the far post 14 minutes from time, was only his fifth league goal of the season.

"You have to realise they don't make it easy for him," said Koeman, who sent on defender Samuel Umtiti in the closing moments to protect Barcelona's lead.

"He's marked by lots (of players). But he's shown he's decisive.

Barcelona are at home to Real Sociedad on Wednesday and full-back Jordi Alba believes the Catalans are heading in the right direction.

Alba told Movistar LaLiga: "The level of the league is good and we are on the right road to move up the table.

"Regardless of what happened in the Madrid derby, we have to do things the right way.

"If we do we'll be up there. We've dropped too many points, that is clear.

"But the league is very open. This year there are teams who have never been as high in the table and they are up there at the moment."

Levante beat Getafe 3-0 last weekend, but that was only their second win of the campaign and the Valencia-based side remain two points from safety.

Goalkeeper Aitor Fernandez said: "We should take pride from the fact they ended the game with three centre-backs.

"That speaks well of the way we played and the game that we played. We made one mistake and they scored, but we must keep showing the same attitude.

"We wanted to move away from the bottom and it was a shame we could not do that."