She has been close before, notably when finishing second at Luhmuhlen on Classic Moet in 2015, and third at Burghley two years ago. But now there's a chance for some bragging rights contests under the family roof.
The win came after a shaky showjumping phase, when several rails were rattled but none fell. The final, decisive phase of a three-day event isn't the horse's strong suit. Indeed it was the combination's first successful jumping round.
But Classic Moet is fast and tore around the cross country layout to set up the victory.
"I certainly had lady luck on my side," said 37-year-old Price, "but sometimes you need a little luck."
The ageless Todd, 62, finished sixth on Kiltubrid Rhapsody, Tim Price and Ringwood Sky Boy were 12th and Todd aboard Leonidas II 14th. Defending champion Andrew Nicholson and Nereo withdrew before the final phase.
Just five of the 53 combinations in the showjumping were clear and inside time.
New Zealand's 4 star eventing champions
Mark Todd 9: Badminton 1980, 1984, 1996, 2011, Burghley 1987, 1990, 1992, 1997, 1999.
Andrew Nicholson 9: Badminton 2017, Burghley 1995, 2000, 2012, 2013, 2014, Pau 2012, Kentucky 2013, Luhmuhlen 2013.
Blyth Tait 3: Burghley 1998, 2001, Kentucky 2000.
Nick Larkin 2: Adelaide 1997, Kentucky 1998.
Caroline Powell 1: Burghley 2000
Jock Paget 1: Badminton 2013
Tim Price 1: Luhmuhlen 2014
Matthew Grayling 1: Adelaide 2001
Clarke Johnstone 1: Adelaide 2017
Jonelle Price 1: Badminton 2018
Total: 29 (Burghley 13, Badminton 7, Adelaide 3, Kentucky 3, Luhmuhlen 2, Pau 1)