By FOX Sports staff
Entering the game at the Sultan Mohammad IV Stadium trailing 4-2 from the first leg, the Red Warriors knew they needed to produce a near-faultless display if they were to keep alive their hopes of retaining the title.
However, they got off to a perfect start when Norfarhan Muhammad fired them ahead in the 19th minute, before Badhri Radzi added a second two minutes after the half-hour mark to level the aggregate score.
A minute before the break, Nigerian defender Obinna Nwaneri ventured forward and scored to make it 3-0 and immediately after the break, Dickson Nwakaeme added a fourth to put Kelantan firmly in control of the tie.
Norfarhan then grabbed his second of the game a minute after the hour mark to end any hopes of an opposition comeback, and although Safee Sali pulled one back for Darul Takzim in the 82nd minute, it was the hosts who had the last say as Indra Putra Mahayuddin weighed in with a sixth goal to cap off a fine performance.
In Saturday's other quarter-final, Sarawak beat Sime Darby 3-1 at the Sarawak State Stadium to advance to the last four after both sides had played out a 0-0 draw in the first leg.
Although it was the visitors who opened the scoring through an Asrol Ibrahim effort after just four minutes, Sarawak equalised in the 26th minute when Muamer Salibasic struck, and it was he who then fired them in front ten minutes after the break.
Six minutes from the end, the Bosnian forward completed his hat-trick to seal his side's progress to the semi-finals, where they will meet Pahang.
In the other last-four clash, Kelantan will take on ATM in a repeat of last year's final.
Saturday's Malaysia Cup Quarter-final 2nd Leg Results
Kelantan 6-1 Darul Takzim (8-5 on agg.)
Sarawak 3-1 Sime Darby (3-1 on agg.)