Second favourite Love has been ruled out of a clash against record-seeking Enable in the Prix de l'Arc de Triomphe on Sunday.
Love's odds had drifted this week from 6-4 to 4-1 after heavy rain made the ground very soft at ParisLongchamp.
The filly was considered Enable's main rival but all her wins this season - in the 1000 Guineas, the Oaks at Epsom and Yorkshire Oaks - were on good ground.
Enable will try to be the first treble winner of Europe's richest flat race.
5-4 Enable (drawn 5), 5-1 Stradivarius (14), 8-1 Sottsass (4), 11-1 In Swoop (1), Serpentine (15); 14-1 Raabihah (2), 16-1 Mogul (3), 20-1 Persian King (7), Japan (11), 40-1 Gold Trip (9), 50-1 Deirdre (12), Way To Paris (6), 66-1 Sovereign (10), 100-1 Chachnak (13), 150-1 Royal Julius (8)
Trainer Aidan O'Brien had indicated on Wednesday night that Love could miss the race over a mile and a half (2.4km) after heavy rain in France.
He has four of the remaining 15 runners - Serpentine, Mogul, Japan and Sovereign- competing for a first prize of nearly £1.5m.
"We just don't know how the others will go on it. When the ground gets that soft you just can't predict," he said.
O'Brien added stablemate Serpentine, runaway winner of this year's Derby at Epsom, to the line-up at a cost of 72,000 euros (£65,000) on Wednesday.
Serpentine was the only additional runner after pleasing O'Brien with his first race since the Derby when finishing fourth to Mogul over the Arc course on 13 September.
Jockey Ryan Moore switches to riding Mogul after Love's withdrawal, with Christophe Soumillon on Serpentine, Yutaka Take aboard Japan and Mickael Barzalona aboard Sovereign.
In Thursday's draw, Enable was allocated stall five, with stablemate Stradivarius in 14.
Enable, ridden by Frankie Dettori for Newmarket trainer John Gosden, won the Arc in 2017 and 2018 but finished second behind Waldgeist last year.
The mare won a record third King George in July before an easy victory in the September Stakes at Kempton.
French trainer Andre Fabre, having dashed Enable's hopes last year with Waldgeist to win the race for a record eighth time, is due to run Persian King - who will be trying the trip for the first time.
Last year's third-placed horse Sottsass, and Japanese challenger Deirdre are among other contenders.
