A section of Barcelona supporters reportedly singled out Lionel Messi for criticism in Saturday's 1-1 draw with Atletico Madrid at the Camp Nou.
The home side needed all three points to win the league title, but were held to a draw by Atletico, who picked up their first league success since 1996.
According to Marca, a section of the Barca supporters became frustrated with Messi in the second period for his perceived lack of effort in the latter stages.
The Argentine recently agreed a new long-term contract with the Catalan outfit, making him the highest-paid player in world football.
However, the former Ballon d'Or winner has struggled to influence the big matches this season.
