How primed for Group Three test How takes a big step up in class when she tackles the Group Three Princess Margaret Juddmonte Stakes at Ascot today. Still a maiden after four starts, the daughter of Galileo has finished second in a pair of maidens at Naas on her last two outings. Trainer Aidan O'Brien said: "She's well. She's starting to get it together and was better the last day. "We think in a better race it might come easier to her as the problem with maidens is that they go slow and she is going a bit quick for herself." Magical Fire, trained by Michael O'Callaghan, is the other Irish runner in the 13-strong field, while heading the home guard is Fair Eva. Roger Charlton admits "the pressure is on" as the daughter of Frankel was all the rage for her Haydock debut in early June and an ultra-impressive display propelled her to the top of ante-post lists for next year's 1000 Guineas. Frankie Dettori takes over in the saddle for the event that is sponsored by the exciting filly's owner Khalid Abdullah. "It will be a very tough race, but she's a nice filly and I've been pleased with the way she has trained," Charlton said. "She was pretty impressive first time out and at the time we didn't know the second was going to win a Listed race and indeed was beaten a length in what was the Cherry Hinton, so the form is pretty good. "The third horse was five or six lengths behind us and has won twice, so the pressure is on. "She's highly rated, she's a nice filly and I hope for the owner's sake she can run really well. "There's been a lot of good fillies around this year. We wanted to run in a novice at Haydock and we were going to run at Newbury but the ground was soft so we scratched that. "I would have just liked to have another confidence-building race but we are into the big time now. "I've very lucky to have a Frankel."