The Barcelona defender suggests the former Real Madrid coach was fixated with promoting a rivalry in press conferences rather than through football
The Portuguese coach, who left los Blancos after a trophyless season to take up his former role at Chelsea, has been famed for his demeanour in press conferences, producing many a famous soundbite.
However, Pique, speaking to journalists in Miami, has intimated that adopting this method was part of the trainer's downfall at Madrid.
"There was a football rivalry, which was strong, but that's just football," the 26-year-old centre-back was quoted by Sport.es.
"Mourinho took this rivalry into press conferences, but football is played on the pitch and you must try to win with the weapons you have.
"This sort of rivalry [through the press] something that had never been seen before in Spain.
"He [Mourinho] wanted to take over the press."
Pique came on as a substitute as Spain defeated Haiti 2-1 in a friendly in Florida on Saturday, with Santi Cazorla and Cesc Fabregas both scoring for la Roja as they prepare for the Confederations Cup later in June.