Trainer Roger Varian enjoyed seven winners across three cards on Saturday - at combined odds of 34,838-1.
He had trebles at Ayr and Newbury, and another victory at Newmarket.
Sakheer's impressive victory in the Mill Reef Stakes at Newbury was among the highlights, six days after Varian won the St Leger with Eldar Eldarov.
Meanwhile, Danny Tudhope became the first Scottish jockey for 50 years to win the Ayr Gold Cup on home turf as Summerghand triumphed.
The 12-1 shot, trained by David O'Meara, came through late to claim victory and Tudhope punched the air with delight as he emulated compatriot Richard Hutchinson who won on Swinging Junior in 1972.
Newmarket trainer Varian said it was "special" to have seven winners on the same day.
"It's been an amazing week with the St Leger and now all these winners in a flash," he said.
"You don't expect that to happen, and especially on a day when the racing is so competitive," he said.
"We'll enjoy it, it doesn't often happen. You can never really expect things to go as well for us as it has today, but everything is clicking."
The record number of winners trained in a single day is 12 - for Michael Dickinson at six different meetings on Boxing Day in 1982.
Varian's seven winners
13.10 BST Newbury Exoplanet 5-2 fav
13:55 Ayr Royal Champion 9-4
14:06 Newmarket Al Husn 9-2
14:15 Newbury Mitbaahy 9-2
14:30 Ayr Dusky Lord 14-1
14:50 Newbury Sakheer 4-5 fav
17:20 Ayr Aimeric 11-4 fav
Combined odds 34,838-1
