The five-furlong contest was as fast and furious as ever, with Son And Sannie blazing the early trail down the middle of the track before his stride just started to shorten reaching the final furlong.
Mokaatil was just hitting top gear at that point and once he assumed the lead, he stretched right out to win by a length and a half.
Only Spoofing took second, with Stone Of Destiny third.
Egan said: “It’s a lovely way to break the duck. It’s my first Dash, so it’s brilliant.
“It’s been a little while coming. I’ve been riding here since I was a 7lb claimer without managing to come home in front, so hopefully they’ll come like London buses from now on!
“He’s a horse that’s been running over six and seven furlongs. He was able to jump the gates well and get a position without me having to put him under too much pressure for the first half of the race. He went way past the line and he’d have no trouble going back up to six.”
Williams admitted he was not certain the Epsom five furlongs would suit his charge, who has also won over six in the past.
He said: “It was a bold move really and we weren’t sure we’d done the right thing, but when the rain came that was going to help him a bit and he’s put up probably a career-best performance, which was great.
“The gentlemen that own him enjoy their racing and we spoke today about coming here and enjoying the moment, see how we go, and they’ve walked away with the winner of the Dash. It’s fantastic, we’re all happy.”
He added: “David did a very good job of getting an early position, he kept him in the race when he could have been taken off his feet and, to be fair, he finished very strongly, like a horse who does stay a bit further.
“I just thought if we were running over this sort of trip, he’s going to want every bit of help he can, he’s not going to be pulling too hard so (the blinkers) worked a treat today.”
“I’d love to say this has been in the book for the last six months and it’s a big plan, but I think we’ve been very fortunate with the way the race has been run and he’s run very well, so we’ll take him home and see what we do next – and what the handicapper does next.”
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