In three pairs of two they went around the Ascot course for the first mile of the Prince of Wales’s Stakes, featured race Wednesday at Royal Ascot. With five-sixteenths of a mile to run the sextet fanned six wide into the home straight, and with a furlong still to race one horse had gone far clear of the other five. Not even money favorite Luxembourg, nor Derby winner Adayar, nor high-class Bay Bridge, but Mostahdaf, running the race of his life to win the Group 1 Prince of Wales in a romp.  Mostahdaf’s first win at the Group 1 level came by four lengths. Luxembourg, one of the best middle-distance horses in Europe, was left reeling after leading, holding second by a half length in this $958,000 fixture.   “I was expecting Mostahdaf to pick up well in the straight but not to make them look like they were standing still,” said John Gosden, who co-trains the horse with his son, Thady. “When the ground dries up, he’s a brilliant horse.”  Adayar got a pocket trip behind Luxembourg and inside American invader Classic Causeway but, like everyone else, was no match for the winner. My Prospero was fourth, Bay Bridge fifth in a subpar performance, and the ambitiously spotted Classic Causeway a distant last.  :: Royal Ascot 2023: Get PPs, previews, analysis, recaps, and more Mostahdaf won six of his first seven starts but in his first two tries at the Group 1 level was 12th in the St. James’s Palace Stakes at the 2021 Royal Ascot meeting and last of 20 in the 2022 Prix de l’Arc de Triomphe. The Arc was no place for Mostahdaf; the horse cannot abide the very soft ground he found that day, and the race’s 1 1/2-mile distance is a touch too far. Distance also hampered him when Mostahdaf finished a respectable fourth behind the world’s best horse, Equinox, in the 1 1/2-mile Sheema Classic on the Dubai World Cup undercard.  Gosden said he’d considered the Group 3 Brigadier Gerard Stakes last month for Mostahdaf but in the end felt the race came too soon after Dubai. Waiting for the Prince of Wales proved prudent. Sitting a comfortable last under Jim Crowley, Mostahdaf toddled along until the field swung into the final straightaway. Already gaining on the leaders before Crowley asked him for anything serious, Mostahdaf made up roughly five lengths in a dozen strides after Crowley pushed the button, going last to first, then sustaining his momentum to the finish.  “We went an even pace and he took me into the race extremely well,” said Crowley. “I may have gone for home too soon, but I didn't want to disappoint him, and he wanted to go.”  Mostahdaf ($26.20) will get a chance to validate the performance in the International Stakes over 1 1/4 miles at York, his likely next start. The 5-year-old, bred and owned by Shadwell Estate Limited, is by Frankel out of Handassa, by Dubawi.  With the Prince of Wales victory, Mostahdaf earned a fees-paid berth in the Breeders' Cup Turf as part of the Win and You're In program. :: Get Santa Anita Clocker Reports straight from the morning workouts at the track. Available every race day.