Johnston filly quick off the mark with course record

A winner at Thirsk last month on her racecourse debut, this was only the third career start for Sheikh Hamdan Al Maktoum's horse who benefited from a typically inspired ride by champion jockey Ryan Moore.

Moore, the Derby-winning rider, had to be at his strongest as Rainfall – the only filly in the field – held off the challenge of Red Jazz on the 8-1 chance.

"I'd looked at the race over the last five years and thought this was a tall order, but she's done nothing wrong since she came to us," said Middleham-based Johnston.

Moore quickly completed a win double when Sir Michael Stoute's Strawberrydaiquiri (9-2) prevailed in the Windsor Forest Stakes.

In the day two highlight, Moore was out of contention as Byword gave French riding star Maxime Guyon victory on his first ride in Britain in the Prince of Wales's Stakes.

The 5-2 favourite, trained in France by Andre Fabre, narrowly denied Henry Cecil's well-fancied Twice Over. A downcast Cecil, seeking his sixth win in the race, thought Twice Over might have prevailed with a clear run; his charge will now look to defend his Champion Stakes crown at Newmarket in October.

Yet, on a day symptomatic of racing's fluctuating fortunes, Cecil was beaming when Timepiece lived up to her reputation in the Sandringham Handicap, the day's finale, following her disappointing Oaks run.

She has disappointed on her three runs this season, but winning jockey Tom Queally went for home early to record an unprecedented 72nd winner at the Royal meeting for Cecil. "I always wanted to train 100 winners here and if it wasn't for 10 years in the doldrums, I might have done," said the trainer.

Queally added: "You wouldn't believe her work in the mornings... she has finally realised her potential."

Earlier, an ecstatic Frankie Dettori got on the scoresheet when Invisible Man, winner of the Nova Display Anniversary Handicap at Pontefract last summer, burst through at the finish to win the Royal Hunt Cup cavalry charge, with Mark Johnston's St Moritz a creditable third.

WHO WON WHAT AT ROYAL ASCOT

2.30: Rainfall

Mark Johnston's horse breaks course record.

3.05: Strawberrydaiquiri

Quick double for Ryan Moore.

3.50: Byword

Winning jockey Maxime Guyon's first ride in Britain.

4.25: Invisible Man

Pontefract winner last year.

5.00: Maqaasid

Two out of two for John Gosden's filly.

5.35: Timepiece

Henry Cecil's 72nd Royal Ascot winner.