Just The Judge gained Classic compensation for her narrow defeat at Newmarket when going one better in the Etihad Airways Irish 1,000 Guineas at the Curragh.
The Charlie Hills-trained filly made amends after finishing second to Sky Lantern in the Qipco 1000 Guineas by landing the honours in emphatic fashion.
Sent off the 2-1 favourite, the strong-travelling Just The Judge scored in the hands of Jamie Spencer from the fast-finishing Rehn's Nest (40-1), with Just Pretending (14-1) third and Big Break just behind in fourth.
"The Coronation at Ascot will really suit her, it's a stiff finish and we can ride a bit of a race on her there" - Charlie Hills on Just The Judge
Spencer had Just The Judge smartly away from her handy two stall and was always prominent as the Elaine Burke-trained Exactement made the running with What Style close up.
While Just The Judge was in the prime position, one of her main market rivals, Big Break, had to overcome a wide draw.
She tried to lay it down to the favourite and looked like playing a major role but could not quite keep up the pace and Just The Judge pulled away in the final furlong.
The Aidan O'Brien-trained Just Pretending held every chance, but was worried out of second place close home by Jim Bolger's outsider Rehn's Nest, who got the runner-pup spot a length and a half behind the winner.
Spencer, who won the race as a teenager on Tarascon in 1998, said: "She's a smart filly. She had the form coming into the race.
"It was never going to be as straightforward as ABC, but I got into a good position and at halfway I was always happy. I followed Seamus (Heffernan on Just Pretending) and it all worked out really well.
"She gives all the signals that 10 furlongs would be well within her grasp and she will be even better.
"She was the best filly at Newmarket bar the winner and she was well on top here today. Hopefully she has a good season ahead of her.
"The Ascot mile is pretty stiff so I'm sure the Coronation is there. We'll enjoy today and see what Charlie and Barry (Hills) and Sheikh Fahad and David (Redvers, racing manager) say."
Hills said: "That was fantastic and I'm so proud of the filly. She's a diamond really and so easy to train, very professional. There's a few more nice races to go for with her.
"I felt sorry for her at Newmarket. She did it the hard way and just got done on the line. It was a big decision coming here and very pleased we have.
"Jamie gave her a peach. He rode her as he said he would in the paddock. He never really had to pick the stick up to her and he gave her a beautiful ride.
"He was in the right position and produced her at the right time.
"The Coronation at Ascot will really suit her, it's a stiff finish and we can ride a bit of a race on her there.
"It's great we've got Sky Lantern to take her on and it will make a great spectacle.
"It's more relief at the moment, but I'm sure I'll wake up in the middle of the night thinking it's great.
"He (his father Barry) will be watching on television and I'm sure he'll have a tear in his eye.
"They (Qatar Racing) have been fantastic over the last few years. They are great supporters of the sport worldwide. It's great to see them get this success.
"As long as she's OK she'll go for the Coronation - it's 26 days away so that's perfect timing."
Sheikh Fahad, the head of Qatar Racing Ltd, who own Just The Judge with the Sangster family, said:
"We said we would come here after Newmarket. She did not see the other filly there but today she showed what she is.
"The filly is much better in her coat now. Hopefully she will only improve.
"If she comes out of the race well then it will be Royal Ascot next. The Coronation is the plan.
"This is our first proper season with Qatar Racing. It is the first Classic for me and my brothers. I think it's a good start."