Trainer Gavin Cromwell maintained his 100% Royal Ascot strike-rate when Snellen (12/1) edged out Pearls And Rubies to land the opening contest on the concluding day of the Royal meeting.
The trainer's only other Royal Ascot runner, Quick Suzy, went on to Queen Mary glory two years ago and was also partnered by today's jockey Gary Carroll.
Dallas Star ploughed something of a lone path towards the far side whilst the Charlie Johnston-trained filly Carolina Reaper led most of the field towards the near side.
Gavin Cromwell's filly was always nicely positioned towards the fore and quickened up to lead entering the final furlong. The well-supported market leader Pearls And Rubies (7/4 F) looked to lay down a stern challenge towards the centre of the track and the pair hit the line together. The Cromwell team were made to wait as the judge pondered the photo, but it was soon determined that Snellen had clung on to score by a head.
However, the judge could not separate the photo for third with a dead-heat called between Richard Fahey's Golden Mind (12/1) and Oddyssey, who defied his starting price figure of 150/1 to share the bronze medal spot.
Gary Carroll said: "I thought I was beaten to be honest. I thought we would all be staying stands' side, but the fancied horses all ended up further away from me. The last half-furlong was a very long half-furlong for me – she was looking for company and started to lean a bit, but she's a very good filly.
"She is a little bit weak and was getting a little lonely when she started rolling. I tried to correct her in Limerick when she went like that and lost momentum. So, I was going forwards and thought, 'keep going', and thankfully I hung on.
"She is only after coming to herself in the last month. We were going to run her in this race first time out but, after running in a barrier trial, the Limerick race presented itself and seemed an ideal starting point. She was very green that day so I'm glad we gave her that run.
"Gavin Cromwell is doing some job with these horses, without a doubt. Whether it's three miles or five furlongs, he gets the best out of everything. But Gavin, all he wants to do is improve, there are no airs or graces. He said he went down and spent a day with Joseph O'Brien, and last year he spent a day with Paddy Twomey, just to try and pick up something. His results are showing.
"[At Royal Ascot] when you get inside the three-furlong pole, there's an energy which comes at you – it gets me going, anyway."
Cromwell said: "Snellen won a barrier trial before Limerick. She has been nice from the word go and is progressing. I think she's going to improve as well."
Went posed to question about whether he has a Classic contender on his hands, he added: "I haven't even thought about it to be honest. We will enjoy today – it's fantastic."
Richard Henry, husband of co-owner Roisin Henry, said of Pearls And Rubies: "She went to win her race, and maybe got a bit lonely on her own. She has run a great race and will come on for the run. She is a sweet filly. Ryan [Moore] thinks she could be very good."
Odyssey's trainer Patrick Owens said: "This is just unbelievable. I have had a lot of faith in this horse – we've only been beaten three and a bit lengths. We were completely overlooked!
"I am so proud of him. I have had faith in this horse since we got him. I gave him a couple of easy breezes in February and then turned him away for two weeks.
"We had a line through a few of these runners. I was happy with the draw, happy with the ground, we had Jim [Crowley] on board, brilliant. Jim has done a fantastic job."
Paddy Power introduced Snellen at 25/1 for Classic glory in the Newmarket's 1000 Guineas next season.