The World Player of the Year equalised with a penalty and settled the match in the last minute with his 29th league goal of the campaign, after Thiago Alcantara had put Barca 2-1 up in a nervous display at the Nou Camp.
Real had put them under pressure by easing through a match that had been expected to be far tougher, when Kaka scored two penalties and set up Cristiano Ronaldo for a third at sixth-placed Bilbao.
"Madrid are going to fight for this league until the end, until it is mathematically impossible because this is the way we have been educated," Real captain Iker Casillas told reporters.
On top of that, Jose Mourinho and Pep Guardiola will have been preparing for the first of four possible meetings between the Spanish giants in 18 days starting with next Saturday's league encounter.
Four days later, they have the King's Cup final in Valencia and they look likely to meet again in the two-legged Champions League semi-finals.
"It was difficult because at this stage of the championship everyone is fighting for something," Barca midfielder Javier Mascherano told Spanish television.
"Almeria are fighting for survival, but we remained calm and quickly equalised after their goal. The important thing is to keep winning games and to keep our pursuers eight points behind us."
"You could have had doubts seeing the starting XI but you can see Madrid has a good squad," Aitor Karanka two told a news conference as Mourinho once again left his number two to face the media.
