Speaking on Monday, Oppenheimer expressed confidence his Derby, Coral-Eclipse and Irish Champion Stakes hero would be triumphant if his favoured conditions prevail.
“If we had good to firm ground, I think we’d win easily. I think we’ve got a great chance,” he said.
“Treve is not that mad on really good ground and is not that brilliant.
“I would be very surprised if we couldn’t beat her and beat her quite well, that’s on good ground, not soft.”
Treve is hot favourite to become the first horse in history to win the Longchamp showpiece three times in Paris at the weekend and Jarnet could not have been happier with his big-race mount after partnering her in her final piece of serious work yesterday.
Told about Oppenheimer’s comments after the workout, Jarnet said: “I’m not so sure about that. When I saw his last race, I was not that impressed.
“Yes, he wins like a good horse, like a tough horse, but now he has run many times already this season and we will see if the Arc might be one race too many for him. However, he is a very good horse.”
Treve followed her lead horse on the grass track of Les Aigles before quickening clear in her usual exuberant style.
Jarnet insists he is concentrating on the race itself rather than Treve potentially becoming the first ever horse to complete a hat-trick in Europe’s premier middle-distance prize.
“We did the same sort of gallop we did last year. I let her gallop and find her stride behind the lead horse and she did her usual thing in the final two furlongs when she quickened well. She is well,” said Jarnet.
“It (winning three Arcs) has never been done before. However, it is not my priority. The most important thing for me is that everything goes well. We would obviously like to fulfil our dream and to win it.”
At the age of 48, Jarnet is in the twilight of his career, but asked whether he could potentially retire from the saddle if Treve does come home in front this weekend, he said: “I have achieved most of my goals, but there is still one race that I would love to win and that is the Prix du Jockey Club.
“However, I’m not going after it as such. We shall see if that it happens or not. Should we win on Sunday, it wouldn’t change anything. I have no plans to stop riding, as there are still many moments to be enjoyed on the track.”
Treve’s trainer Criquette Head-Maarek also gave her seal of approval to the morning blow-out.
She said: “My impression is good. She is well, she was not pulling, she was very relaxed.
“Thierry thinks she is in top form, so let’s keep our fingers crossed.”
Leading owner Khalid Abdullah has won the Arc four times with Rainbow Quest (1985), Dancing Brave (1986), Rail Link (2006) and Workforce (2010) and could yet fire a twin assault at this year’s renewal.
Andre Fabre’s French Derby hero New Bay is widely regarded as Treve’s biggest threat from her own country after a runaway victory in the Prix Niel earlier this month.
Abdullah’s racing manager, Teddy Grimthorpe, admits the three-year-old will need to take his game to another level to deny Head-Maarek’s mare the hat-trick.
He said: “We’ve got to find more than we’ve ever found. It depends on Treve and how she performs, but on the whole, to win an Arc, most horses have to produce a lifetime best.”
Abdullah and Fabre could also be represented by the admirable Flintshire, runner-up to Treve in last year’s Arc and in the Grand Prix de Saint-Cloud back in June.
“I would imagine if Andre is still happy with him and the Prince is happy, it’s a possibility we’ll run them both,” Grimthorpe said.
“Vincent (Cheminaud) would have the call on which one he would want to ride, but I would imagine he’ll want to ride New Bay. If that was the case, I would imagine Maxime Guyon would ride Flintshire, hopefully.”
Treve, New Bay and Flintshire were all among the 20 horses to stand their ground at the latest forfeit stage.
The only British-trained entrants are John Gosden’s duo of Jack Hobbs and Eagle Top, although Golden Horn is expected to be supplemented tomorrow at a cost of €20,000.
Aidan O’Brien has Tapestry and Found in contention, while Dermot Weld’s Free Eagle and the John Oxx-trained Sea Moon are also potential challengers from Ireland.