Veteran Cirrus Des Aigles has inflicted the first defeat on Treve in the Group One Prix Ganay at Longchamp.
Making her first appearance this year, Treve was getting 3lb (1.5kg) from Cirrus Des Aigles but could not take advantage as her race-fit rival edged her out in a thrilling battle up the straight.
It looked as though Treve's class would see her through against Cirrus Des Aigles but, with the benefit of two runs already this year, he battled back to win by a short neck, with Norse King 4-1/2 lengths back in third.
Winning trainer Corine Barande-Barbe felt the early pace had suited Cirrus Des Aigles and is now eyeing a trip to Epsom for the Coronation Cup on June 7.
"I'm very proud of what he did today - he never was better," Barande-Barbe said.
"I thought the strong pace helped us and it was obviously one of his finest moments."
Head-Maarek felt the ground might have gone against Treve and said she was confident of avenging the defeat should the pair clash again this term.
"Maybe there was too much rain. It was sticky out there and we had too much ground to make up," she said.
"The winner had had two races already and the fitness was there.
"If she comes out of it well, in principle we will be going to Royal Ascot. We might have lost a battle, but we haven't lost a war.
"In the rematch, I'm sure we can get it back. She took the lead but in the end he's come back at us - that's racing. Horses are not unbeatable, that is for certain."