Crimson Advocate (9/1) became the fifth US-trained filly to win the Group 2 Queen Mary Stakes after clinging on by the narrowest of margins in a thrilling finish.

The George Weaver-trained juvenile showed blistering speed and established a clear lead on the stands’ side entering the final furlong. However, her stride started to shorten and she was joined close home by the fast-finishing Relief Rally.

Crimson Advocate had her head in front on the line to give her trainer a first Royal Ascot success, while it was a fourth victory at the meeting for Hall of Fame rider John Velazquez.

Relief Rally was devouring the ground late on under Tom Marquand and was in front a yard after the line but the head bob went against her. Beautiful Diamond, sent off the 11/4 favourite, kept on well to finish two lengths off the front pair in third.

Weaver said: “I have so much respect for the horses over here. It always seems like the European horses are better grass horses than what we have, but I knew our filly was very talented and I was hoping that she would be able to get the job done. Don’t get me wrong, the way she won at Gulfstream, I was very excited about her, but like I said, I have tremendous respect for the trainers and horses that are over here.

“I came here eight years ago with a horse [Cyclogenesis] that wasn’t good enough. I thought it would be great if I could ever come back with something that was, and we did. When you try to plan things, you try to buy horses for Ascot, it never works out. Things just come together, and this year we’ve got two nice horses to bring over here.

“Royal Ascot is Royal Ascot, what can you say? You can feel the electricity when you’re here and how special it is, and it’s a beautiful feather for us to have in our cap. It’s not the biggest purse I’ve ever won – Vekoma was a tremendous racehorse and I won the Dubai Golden Shaheen early on in 2005 [with Saratoga County]. I’ve had some great moments, but this ranks right up there.”

Velazquez said: “That was close, but I'm glad Crimson Advocate held on. We knew she was going to be really fast coming out; we tried to get her on the best path for the firmer ground. From yesterday to today, the turf is a little bit firmer, so it’s better for our horses and she showed up today.

“I rode two races yesterday and the ground was a little soft for our horses – Wesley Ward’s horses break fast and they had a hard time to keep the pace. Today is a little drier and our horses handle it better.

“I saw her run in Florida when she won, and I was like, I want to ride that horse at Royal Ascot! I actually texted the trainer right away saying I wanted to ride her.

"In the race she was going so well, but I probably made a little premature move thinking I would get away from them and then hold on. In hindsight, I almost messed up the race and should have waited. She handled it better than I did!

"It's great to be here and to have another winner, and it's great for George. His wife had a very bad accident a year and a half ago and they didn't think she would walk again, so for her to be here is a miracle.

“It is a dream come true coming here and I try to come whenever I can. It is a special place and it’s great to come here and have winners.”

Relief Rally’s trainer William Haggas said: “We were in front before, and after the line, but not on. There you go, that’s the way it is, she’s run a great race and made up a lot of ground in the last furlong.”