David Probert stunned horse racing punters with a five-timer at odds of 257-1.
At his home track, Ffos Las, the 33-year-old raced to victory in successive contests on Wednesday evening.
Three of his wins came on horses trained by Hughie Morrison, whose Quarantini (3-1) started the run with a determined effort in the Check Our Premier League Markets At starsports.bet Handicap.
The stable's Hesperis (15-8f) travelled smoothly on the way to her Call Star Sports On 08000 521 321 Handicap triumph, while another favourite Shuthoor justified shorter odds of evens in the Star Sports Bet Owners Club Guarantee Maiden Fillies' Stakes.
Fourth to strike was the Tom Ward-trained Roman Mist (2-1jf), two-and-a-quarter lengths too good for the opposition in the Star Sports Bet Pipped?! Offer Handicap.
And Morrison's Curtiz (11-4) rounded off the night, getting his head in front right at the finish to the Download The Star Sports App Handicap.
Probert told Sky Sports Racing: "I have never done it before and I knew I had some really good chances this evening when I d id come racing, but to have five winners I have to pinch myself."
Before the feat, Probert was already enjoying a memorable season, riding his first Royal Ascot winner aboard Sandrine in the Albany Stakes.
The Classic contender is set to put her unbeaten record on the line at York's Ebor Festival next week.
Probert only passed the 100-winner mark for the current campaign this week, having reached 1,000 career successes in 2020.
Probert's rides on Thursday and odds from Grovesnor Sport*
1.00 Hey Teacher 3-10
1.35 Damned Elusive 7-1
2.10 Great Havana 5-2
2.45 Wild Flower 11-2
3.20 Red Walls 9-1
3.55 Ebqaa 9-1
4.25 L'Operateur 11-2
*Latest odds, subject to change
