Ernesto Valverde played an almost full-strength side as Barcelona travelled to their rivals for the Copa day Rey quarter-final first-leg clash.
And the La Liga leaders had the majority of possession and chances but could not find a way past the home goalkeeper.
Even Messi had a penalty saved on the hour mark, before Espanyol struck the winner three minutes from time.
And the Argentina international was said to be furious after the loss and demanded that one player never play for the club again.
According to Spanish outlet Diario Gol, Aleix Vidal is the man Messi wants sold.
The report adds that boss Valverde is also not keen on utilising the Spaniard, especially as he failed to perform during a rare start.
It is suggested that he did not combine well with his team-mates nor create any chances for the attackers.
Messi believes that Sergi Roberto, who was playing in a much deeper role, had a bigger impact.
Barcelona will have a chance to bounce back from the defeat in the second leg in two weeks’ time.
But first they travel to Real Betis in the league on Sunday (7.45pm).