Siskin won the Tattersalls Irish 2,000 Guineas for Ger Lyons and Colin Keane, overcoming a troubled passage to do so by a length and three quarters.
Vatican City (14-1) was second and Lope Y Fernandez (9-2) was third.
It didn't look a strongly run contest and the field were in a heap with two furlongs left to race. Fort Myers and Royal Lytham were at the head of affairs, but under pressure when the run to the line began in earnest.
Seamie Heffernan then committed on Lope Y Fernandez and had first run on Siskin, who had to give Armory a nudge to get racing room. When he did see daylight, the response was immediate. Vatican City also finished well to grab the runner-up spot.
Owned by Khalid Abdullah, the son of First Defence provided Lyons and Keane with a first Classic success and added to his Group One victory in the Phoenix Stakes over six furlongs at the Curragh as a juvenile.
Lyons said: "This means everything, it means 30 years' hard graft for everybody - to win a Guineas was always my number one and hopefully it's the first of many.
"I'm delighted with the support we are getting from owners and the quality has increased year on year.
"That was hard work and full credit to Colin Keane. You don't get a Guineas handed to you and they both stood up when it was needed. If there was a kink in that horse then he wasn't going to go through that gap.
"Colin is the best there is at the minute. He's only a kid and he's going to keep improving.
"I also want to thank Khalid Abdullah, who is watching in Paris, I'm sure. They are the ultimate breeders."
Siskin had never previously run beyond six furlongs, and Lyons went on: "I was worried about this horse's trip around February and March, but when we went into lockdown then I was confident that the trip wasn't an issue. If we were a sprinter then we were in trouble because we weren't quick enough.
"He's a very easy horse to train and no question he's the best I've trained.
"We'll probably go to Goodwood next for the Sussex, but I want to keep Colin on him and hopefully the 14 days (quarantine) will be gone by then. We are definitely skipping Ascot.
"We'll have a chat about it, but that was the plan providing he was good enough today.
"I know he gets the mile and I wouldn't draw a line through 10 furlongs at the moment."
Here's how Siskin won a terrific Irish 2,000 Guineas at the Curragh #RTEracing pic.twitter.com/KBBM2NDk09
— RTÉ Sport (@RTEsport) June 12, 2020
Crossfirehurricane (7-1) is set for a venture into Group One company after an impressive performance in the Coolmore Ten Sovereigns Gallinule Stakes.
Taking his unbeaten record to four, the Joseph O'Brien-trained colt was given a patient ride in the 10-furlong Group Three contest by Shane Crosse, who did not panic when Toronto opened up a sizeable advantage at the head of the six-runner field.
Twice successful on the Polytrack at the Dundalk in February and racing over a trip in excess of a mile for the first time, the son of Kitten's Joy made smooth progress down the straight to join Gold Maze as Toronto gave way and ultimately came out a length and a quarter to the good.
The winning trainer flagged up the Tattersalls Gold Cup on 26 July as a potential target.
He said: "He's an improving colt. I was a little bit worried about experience and the trip coming here, but Shane gave him a lovely ride.
"He had a setback after he won his maiden last year and as a result he missed most of last season. We gave him some experience on the all-weather and he won twice up there (Dundalk).
"We were a bit worried about the trip and left him in the Guineas. I'd say this is going to be his trip.
"I'm not sure I'd be going a mile and a half with him, and we'll be looking for another race at this trip where the ground is nice and quick.
"The Tattersalls Gold Cup back here is an option for him and he could have another run between now and then."
A double on the card for both Joseph O'Brien and @CrosseShane 🔥
— The Curragh Racecourse (@curraghrace) June 12, 2020
Crossfirehurricane stretches his unbeaten record to four in the @coolmorestud Ten Sovereigns Gallinule Stakes 🏆 pic.twitter.com/C81sOelN8b
Admiral Nelson (5-1) staked a late claim for Royal Ascot as he accounted for a better-fancied stablemate in the Tally-Ho Stud Irish EBF (C&G) Maiden.
Aidan O'Brien fielded three newcomers in the five-furlong contest, with Merchants Quay appearing to be the yard's first string with Seamie Heffernan aboard.
However, it was Wayne Lordan's mount who impressed the most, travelling stylishly and moving with authority at the finish to win by a cosy length from Merchants Quay.
O'Brien said of his winner: "He travelled well and could be a Coventry horse. It will depend how he comes out of this and he'll have to go straight to Ascot. He won't be doing anything after this because it is so close.
"It's far from ideal, but we are lucky to have got a race into them. We have run two or three in each of the races (since racing resumed in Ireland on Monday).
"It's different times, but we are lucky to have the races."
He added: "We think the second is a nice horse as well. Seamus said he was just a little bit in his hands and maybe travelled a little bit too strong. It's possible he could go as well (Royal Ascot), but they may not all get in."
Joseph O'Brien got on the scoreboard via Galileo Chrome (4-1) in the 10-furlong Irish Stallion Farms EBF (C&G) Maiden.
The winner was fifth on his only start last year, but stepped up on that to claim a head verdict over King Of The Throne in a thrilling finish.
O'Brien said: "He'd a lovely run last year and had wintered well. He was working nicely and we thought he was a pretty nice maiden.
"He's entered in the Derby here and you would have to take it into consideration, but it would be a big enough ask for him to step straight in there after today.
"He's a nice colt and a middle-distance type horse. A mile and a half would be no problem to him. He would be better going further and is still a big baby. I like him a lot."
Bowerman (5-1) continued his progression to land the Paddy Power Irish Lincolnshire.
Last seen just missing out on a Listed prize in France in February, the Adrian McGuinness representative burst clear when getting a gap over a furlong out and quickly put the valuable handicap to bed.
McGuinness said: "He's 6lb better lighter on the grass and we always felt there was a big pot in him. He's a very high-class horse and I'd say his handicap days are over now.
"Our original plan was to run in the Lincoln at the start of the year and then go for the Royal Hunt Cup, but I'll settle for this!"
Jessica Harrington and Shane Foley can do little wrong at the moment - a point emphasised through Leo De Fury (6-1) in Coolmore Magna Grecia Irish EBF Mooresbridge Stakes.
Harrington's daughter, Kate, said of the emphatic winner: "He's really exciting. We thought a lot of him last year and the ground was a bit soft for him at the back end in Longchamp, but he's wintered really well and I can't believe he's won so easy there.
"Shane said he just dropped him in. I thought there was something wrong as they went so hard and he was so far back, but the way he got there he looks like a proper horse.
"I'd say the Tattersalls Gold Cup will be his next aim. We'll give him a bit of time between his races."
