The Aidan O’Brien trained 3-year-old strode out around the final corner to win by a staggering 18 ½ lengths from Rayya with Reride in third.
The finishing time of 1:55:18 broke the existing mark of 1:56:51 set by Mizbah last year,
The pre-match favourite, and local hero, Godolphin’s Gold Town wilted badly to finish a disappointing fourth.
Mendelssohn, the sire of Scat Daddy, will now set his sights on the Kentucky Derby on May 5.
O’Brien confirmed after his Breeders’ Cup Juvenile Turf success that the Derby was under consideration and following a comeback success at Dundalk in early March, Mendelssohn took the next step on the road to Churchill Downs in this nine-furlong Group Two.
One of the best performance in Dubai World Cup night. It will take some horse to beat him in the Kentucky Derby. Brilliant win.— Alex jones (@ajax1964_alex) March 31, 2018
Jockey Ryan Moore appeared keen to get Mendelssohn to the lead from the moment the gates opened and he soon navigated his way to the front.
From that point it was a matter of margin rather than result, as one by one his rivals fell away as the US challenger galloped on impressively.
Most remarkable about the run was that it was Mendelssohn’s debut on dirt.
But the further Mendelssohn went the better he looked and he passed the post a long way clear of Rayya to score in a course-record time.
Afterwards the usually staid O’Brien worked hard to contain his delight.
“Ryan was happy he had a good draw and if he broke well he was happy to let him travel in front,” said the Irishman, “he gave him a great ride – we couldn’t be happier.
“He came forward lovely from his first run and that was good experience for him on that surface first time.”
Moore said: “He’s a very fast horse. He could have led a Breeders’ Cup Juvenile Turf if I’d wanted to.
“It’s the first time he’s been in front today and he’s still a horse that’s learning, so he was still a bit green in places. It was his first run on dirt, so that was huge for him, and it was his first time at this trip, so that was another question mark.
“He’s a high-quality horse who has got better with every start.”
Looking ahead to a possible tilt at the Kentucky Derby, the jockey added: “Obviously the next time it’s going to be a far tougher question, there’s no doubt about that, but we’re very happy with what he’s done and I still feel he will get better.
“He’s got the pedigree and the looks to go with the form that he’s producing, so he’s a very exciting horse.”
It was Moore’s second win of the day after he got local horses off to a great start with Heavy Metal taking out the Godolphin Mile for Sheikh Hamdan bin Mohammed Al Maktoum in the first race of the day.
The GCC again triumphed in the Dubai Kahayla Classic with a strong ride from Saudi Arabia representative Tallaab Al Khalediah, trained by Mutlaq bin Mashraf and ridden by Roberto Perez.
Dubai Gold Cup (G2) to Vazirabad, who makes it a hat-trick on wins of World Cup Day..by Manduro (Monsun). Dam by Linamix, group winning half-sister to G1 winner Varenar, going back to a half-sister to Swale..— Pedigree Consultants (@Pedigreeconsult) March 31, 2018
The ride of the day, prior to the Mendelssohn masterclass came in the third race, when Vazirabad made it an historic hat-trick of wins on Dubai World Cup day in the Dubai Gold Cup over 3200m on turf.
Trained by Alain De Royer-Dupre and ridden by Christophe Soumillon, the French gelding charged down the straight, vanquishing Godolphin’s Frontiersman (fourth) and Rare Rhythm (third) who had led into the final 300m.
Sheikzayedroad held on for second for the UAE, trained by David Simcock and guided by Martin Harley.
There was a sensation just moments before race five, the Al Quoz Sprint, as the favourite – Godolphin’s Blue Point – was scratched at the gate with blood in his nostrils. Trainer Charlie Appleby and jockey William Buick must have started to think it wasn’t there day.
But Appleby was not to be denied with James Doyle bringing home another of his runners, Jungle Cat – the Godolphin horse cheered on by a overjoyed crowd.
Trainer Peter Miller filled out the minor placings with Stormy Liberal second and Conquest Tsunami third.
Know more about Sport360 Application