PROGRESSIVE four-year-old Mutahadee (Encosta de Lago), last seen finishing runner-up in the Group 1 Dubai Duty Free on March 31, died suddenly Monday morning.

Trainer Tommy Stack’s website broke the shocking news, revealing that Mutahadee “collapsed after a routine exercise on the gallops” at his Thomastown Castle base in Ireland. A $117,152 Goffs Orby yearling purchase by Sheikh Mohammad bin Khalifa al Maktoum, the well-bred colt began his career under Stack’s direction, and showed himself a smart prospect when placing in last summer’s Group 2 Royal Whip Stakes in only his third career start.

Mutahadee was transferred to Mike de Kock in advance of this year’s Dubai Carnival, where he bolted up in two handicaps before tackling top company. He was too far off a dawdling pace in the Group 1 Jebel Hatta, but still flashed home for third, and next time, he beat all bar the impressive course record-setter Cityscape (Selkirk) in the Duty Free.

Mutahadee, who amassed more than $1.2 million from his 8-3-1-3 record, rejoined Stack in early May for a European campaign. “Both team Stack and de Kock are sad to see him gone,” Stack’s website eulogized.

Photo: Mutahdee (yellow silks), winning in Dubai. (Andrew Watkins).