Mother Earth displayed her class once again to take the Group One Prix Rothschild at Deauville.
The filly started as the 19-10 favourite under Ryan Moore and travelled towards the rear of the group for much of the race before being guided through a gap in the field with just over two furlongs remaining.
Having taken up the lead, Mother Earth was challenged by a trio of rivals in the closing stages of the contest, with Sagamiyra, Speak Of The Devil and Rougir all closing.
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Aidan O'Brien's runner prevailed, crossing the line a head in front of Sagamiyra, with Speak Of The Devil a further short head behind and Rougir the same distance away in fourth.
The victory follows Mother Earth's 1000 Guineas win at the beginning of the season, after which she was second in the Poule d'Essai des Pouliches, third in the Coronation Stakes and runner-up in the Falmouth Stakes.
O'Brien told Sky Sports Racing: "Ryan gave her a brilliant ride. She's a very professional filly and settled very well.
"When she gets to the front she waits a little bit but that's not a bad point. I think we'll probably stay at a mile. She likes the pace that they go."
Ed Walker's Primo Bacio, fifth in the Falmouth Stakes last month, appeared to struggle in the ground - described as good to soft - as she finished down the field in seventh.
There was British success earlier on the card at Deauville as George Boughey's Oscula - also ridden by Moore - took the Group Three Prix Six Perfections, beating Andre Fabre's hot favourite Zellie and Simon and Ed Crisford's Daneh.