Sadly, unless he mangled the words of institution, or, unless he is not validly ordained, he consecrated the Eucharist validly. A priest would validly consecrate even if he were intending to later desecrate a host. It is horrifying, but true. This is the power conferred on priests when they are ordained, which can never be taken away, even by laicization. This is why bad candidates need to be weeded out when in seminary (or, preferably, when applying to seminary).

@Joao Machado The intention to do what the Church does is satisfied by speaking correctly the sacramental form, with the intention of confecting the Sacrament. It does not extend to having good intentions besides. If a valid priest were to be able to “say the black, and do the red,” as far as the essential form goes, but not to successfully confect the Sacrament due to some flaws in his interior disposition, then trust in the Sacraments would erode horribly. Those who profane the Sacraments need to be stopped, largely because they are, truly, desecrating them, not because they’re simulating them.