Mbappe is being blamed for Real's struggles this season as he battles to adjust after arriving in the summer from PSG.
“He is facing strong criticism in both France and Spain, as he is not at his best. Currently, he is not decisive for Real Madrid and is not scoring or creating many goal-scoring opportunities,” Pires told MBC MASR 2 of Egypt.
“Real Madrid fans had high expectations for Mbappé since his arrival at the Merengue team. However, changing country, team and teammates is not easy, especially when it comes to a club with the best players on the planet.
"Mbappé must face these criticisms, change his style of play , recognize that he is not at his best and improve his performance.”
Asked whether Mbappé made a mistake by joining Real Madrid, considering the presence of a fully-fit Vinícius Jr, Pires continued: "Mbappé dreamed of playing for Real Madrid.
"He knows perfectly well that Vinícius, who is an exceptional player, plays in the same position as him, is decisive and scores a lot of goals. Mbappé must adapt to this situation and to the different tactics of the team. Turning down Real Madrid is difficult for any player.
"The solution is for Mbappé to adapt to Real Madrid's tactical style , and it is (coach Carlo) Ancelotti's job to find tactical solutions that suit both Mbappé and Vinícius."