The win was JDT's 7th successive league victory and it only served to highlight the huge gap between the 5-time champions and the rest of the league.
Even though Kedah were playing at home, the fact that they were without the service of Liridon Krasniqi only made the task harder as Raul Longhi opted to put out his best available starting eleven.
Fernando Marquez put Gonzalo Cabrera through in the 21st minute and the latter easily slid the ball into the net for JDT's opening goal.
The Southern Tigers doubled their lead seven minutes before half time after Azrif Nasrulhaq's pinpoint cross found Marquez who thundered in a header from close range.
JDT eased off in the second and were almost punished when Kedah were awarded a penalty after La'Vere Corbin-Ong was shown his second yellow card for fouling Rizal Ghazali. But Paulo Rangel's subsequent penalty was well pushed away by Farizal Marlias.
The Red Eagles would get a second stab at it when Rangel was fouled inside the box in the 77th minute and this time, Sandra da Silva step up to put away the ensuing penalty.
Yet there was more drama in the aftermath of the penalty as Rangel was deemed to have barged into Farizal in trying to retrieve the ball and shown a straight red for his troubles.
A 10-man Kedah could do little to prevent JDT from gaining their 16th league win from 19 matched played.