Pat Smullen brought the daughter of Azamour to head long-time leader Together Forever a furlong from home and storm to victory by a length and three-quarters.
Together Forever roared off in front and was at least eight lengths clear at one stage. Smullen decided not to give Aidan O’Brien’s charge too much rope and settled his filly in second place.
It proved a wise move as Covert Love (7-1), who was supplemented for the race, got first run on her rivals and bounded away to take her winning run to four.
She won readily from Jack Naylor, with 15-8 favourite Curvy a head away third.
“I’m to be married next Saturday so this is the last time I can ever say this is the best day of my life,” said Palmer.
“I’m terrified I’ll wake up and find myself still in my bed in Newmarket. I couldn’t be more excited.
“Aidan’s horse (Together Forever) went off like a scalded cat and I loved the way Pat took her back and made his own running and let that one go as a hare.
“There’s still time to put her in the St Leger. We might wait and see what the weather does in August and maybe think about the Yorkshire Oaks.
“We paid €40,000 to come here as a supplementary entry. At that point that was every penny she had won in prize-money.
“I’m delighted the syndicate allowed us to do it.
“She’s a lightly-raced, young filly. I genuinely believe her biggest days, if they get any bigger than this, could well be ahead of her.”
Smullen said: “We were very confident the filly would stay.
“Her stamina was unbelievable. There’s more improvement in her.
“It’s great to win a Classic here on your home track.”
Stepper Point (6-1) returned to his best with a battling victory in the Invincible Spirit Sapphire Stakes.
William Muir’s seasoned sprinter had been out of luck since winning the Flying Five over this course and distance last September, but hit back with a neck call over favourite Mecca’s Angel.
Smullen, who also struck earlier on the card with Have A Nice Day, said: “All he had to do was come back to his old form of last year and he’d be very competitive.
“The ground is drying out rapidly. I thought we’d put it up to the favourite as he might not enjoy conditions and it worked out.”
Final Frontier (5-6 favourite) followed up his debut success when surviving a stewards’ inquiry to claim Group Three honours in the Jebel Ali Racecourse & Stables Anglesey Stakes. Jessica Harrington’s colt just kept the Ger Lyons-trained Miss Katie Mae at bay by a neck under Shane Foley as the pair came close together in the closing stages.
“He’ll definitely step up to seven now and you’d imagine he’ll go for the National Stakes here,” said Harrington.
Aidan O’Brien’s Shogun (6-4 favourite) looked a thoroughbred of limitless potential after he skipped two and a quarter lengths clear in the Darley EBF Maiden under the trainer’s son Joseph.
“He was a complete baby the first day and didn’t know what was going on,” said the Ballydoyle handler.
“I’d say he’s very smart – he always showed that he’s very smart. He could step into the Futurity and those races. He’s a big, mature horse.”