Rosdhu Queen made almost every yard to land the Jaguar Cars Cheveley Park Stakes at Newmarket.
The form of the Lowther Stakes at York had taken a few knocks but the Knavesmire heat, not for the first time, proved key to this six furlong Group One contest.
Rosdhu Queen had run out a length and three quarter winner from Bailey's Jubilee on that occasion and it momentarily looked as though Mark Johnston's filly would reverse the form.
Rosdhu Queen, however, found more once challenged and had a length in hand at the line from the rallying Winning Express who edged out the Johnston runner by a nose for minor honours.
The William Haggas-trained winner missed a beat at the start but was soon tanking along at the head of affairs under Johnny Murtagh as the field raced in two groups.
The runners joined together at the two furlong pole, which was bad news for the 2-1 favourite Maureen as Richard Hughes' partner was left with nowhere to go.
It looked as though the leader's exertions might tell as she hit the rising ground and the eventual third challenged but the Invincible Spirit filly had enough petrol in the tank to pull away and stretch her unbeaten run to four.
When asked if he thought the winner would develop into a Qipco 1000 Guineas contender next season the trainer said: "I thought we ought to enjoy the moment. We'll consider that over the next four months.
"She's a very tough and genuine filly. To be fair I didn't think she'd stay six furlongs but in the Lowther she did and went again and I think there's a bit more to come. Whether she's a Guineas filly I don't know but she's a Group One winner now."
Sky Bet cut the winner to 20s from 25s for next year's Classic but Betfred were more impressed and go 14s from 25s.
Ed McMahon had supplemented Winning Express for the race after her Listed victory at Salisbury, and he was a touch disappointed.
"The winner just injected a bit of pace going into the Dip, and I'm not saying she was caught flat-footed but she just tends to switch off," he said.
"Franny (Norton, jockey) said she was doing her best work at the end and in another 20 yards she would have got there. We could be an unlucky loser.
"I'm not sure her breeding suggests she will get a mile next year but she will certainly get seven furlongs. That's it for the year."
Mark Johnston said of Baileys Jubilee, who has been on the go since the start of the season: "I'm very pleased with her. My impression was she doesn't stay and Kieren (Fallon) said she didn't in the past but he said she switched off lovely once she got behind one. That will be it now, and she'll go straight for the 1000 Guineas."