Ryan Moore rode a record ninth winner of this year's Royal Ascot meeting aboard Aloft in the Queen's Vase.
Lester Piggott set the previous post-war best of eight winners in 1965 before repeating the feat a decade a later and Pat Eddery matched that total in 1989.
Aidan O'Brien's three-year-old was the 5-2 favourite for the two-mile contest, despite stepping up a full mile in distance and making his first start since finishing second in the Racing Post Trophy at Doncaster last October.
Moore rode a patient race aboard the market leader before asking for maximum effort from the home turn.
It was hard work over the marathon distance, but Aloft responded admirably considering his lengthy absence and got up to beat Tommy Docc and Future Empire by half a length and the same.
Moore said: "It was a very messy race, I was slowly away and in a bad position and having to pick my way, he was a bit rusty all the way round.
"He's a fair horse this fellow. He's open to all sorts of improvement, it's his first run of the year and you wouldn't know where he could end up.
"I'm very lucky, I get to ride the best horses and that makes a big difference."
And with six rides to come on Saturday, it is possible Moore could go on to break the great Fred Archer's overall record of 12 Royal Ascot winners, which dates back to 1878.
O'Brien has provided Moore with five of his winners this week, and he said: "What can I say about Ryan? He's a marvellous jockey, probably the greatest jockey I've ever seen. He's a total professional and fully committed.
"He has great feel about a horse and great feel about a race," said the trainer.
"He's an absolute gentleman to work with and always has been. We've worked with him very closely for the last three years and we're privileged he's riding for us."
"Ryan Moore is a brilliant jockey, anyone can see that" - Lester Piggott
The three-time champion jockey, who rode his first winner over jumps at Towcester as a 16-year-old, arrived on Tuesday having previously ridden 27 Royal Ascot winners and been top jockey at the meeting on four occasions.
He got off the mark for the week aboard dual Guineas hero Gleneagles (8-15 favourite), who was a stunning winner of the St James's Palace Stakes, before completing an opening day treble aboard Ascot Stakes scorer Clondaw Warrior (5-1 favourite) and Windsor Castle victor Washington DC (5-1).
A Wednesday double featured triumphs on imposing American filly Acapulco (5-2 favourite) in the Queen Mary and 8-1 shot Gm Hopkins in the Royal Hunt Cup.
Moore supporters were in clover on Thursday as the jockey booted 12-1 chance Waterloo Bridge home in front in the Norfolk Stakes and later scored on Ribblesdale Stakes heroine Curvy (9-2) and 10-1 shot War Envoy in the Britannia.
With five rides booked for the penultimate day of the meeting, Moore looked to have every chance of clinching more glory and although he went close aboard Coronation Stakes runner-up Found, he had to wait until the last race of the day to break the record.
Piggott himself said: "Ryan Moore is a brilliant jockey, anyone can see that. To win nine races during any week is a fantastic achievement, but to do it at Royal Ascot where the competition is so tough is extremely impressive.
"I'm sure Ryan will go on to break many more records during his career."
Moore has taken up an increasingly prominent role in O'Brien's powerful Ballydoyle operation this year, riding principally for the Coolmore triumverate of John Magnier, Michael Tabor and Derrick Smith.
Magnier said: "Ryan is a very modest guy, and regardless of what anyone says about him he has a great sense of humour. He's good company as well as being a good jockey."
Tabor added: "You can't add any more superlatives - we've seen just brilliant riding all week.
"And, dare I say, he's been very unlucky in a couple of races, but that's always going to happen."
Smith was particularly effusive in his praise.
He said: "He has a tremendous amount of talent. He's right up there. I've seen them all, Lester, Mick Kinane, Johnny Murtagh, Frankie Dettori - he's right up there with all of them."
