When you talk about Hazrat Mahdi (pbuh) you will be aware of the antichrist (dajjal); when you talk about the dajjal you will be aware of Hazrat Mahdi (pbuh). These two constitute a whole. I mean everything is created with its contrast; like day and night, or good and bad. If there is a dajjal, there absolutely is a Mahdi; if there is a Mahdi, there absolutely is a dajjal.
(A9 TV; May 19th, 2014)