Christophe Soumillon sees Mishriff as the biggest danger to Vadeni, who bids to follow up his Coral-Eclipse success in the Irish Champion Stakes at Leopardstown on Saturday.
The big-race jockey teamed up with trainer Jean-Claude Rouget to take the 10-furlong Group One prize with Almanzor in 2016 and the duo have a leading chance of lifting the laurels again.
Vadeni caused something of a surprise in the French Derby, scooting clear to win by five lengths at Chantilly, having previously taken a Group Three prize.
A son of Churchill, the Aga Khan-owned colt backed that up with a neck success over Mishriff in a deep renewal of the Eclipse at Sandown and has been kept fresh since.
Soumillon said: "It was a surprising win in the French Derby and he won amazingly well that day.
"Since that day we are dreaming high because it is not very often that you can see a horse winning a Group One with this kind of keenness.
"We went to Sandown hoping he was in the same good form and he produced exactly what we were hoping for.
"It was a very strong race – there was not a lot of runners, but the quality was high. I think it was probably the best Eclipse we have seen for a long time.
"The pace wasn't crazy and that’s why we all finished together. It was a little bit tactical, but it was a great moment again.
"He is quite easy to ride and very straightforward. He has a very calm character and is very professional."
There is a similarly select field of seven who face the judge this time, although the Belgian-born rider feels that Colin Keane’s mount will prove Vadeni’s biggest obstacle to completing a four-timer.
"I think Mishriff will be the main danger for me," said Soumillon. "He was a bit unlucky at Sandown.
"He ran well last time although he got easily beat by Baaeed (in the Juddmonte International), but he should be one of the horses to beat in the race.
"They have a good draw. He will in a good position, probably, in the race and hopefully the pace will be good enough for everyone to have every chance."
With James Doyle still nursing a hand injury, Keane will come in for the ride aboard the Prince Faisal-owned Mishriff, who has won three times at the top level and also claimed the world’s most valuable race, the Saudi Cup, in February last year.
Prince Faisal’s racing manager, Ted Voute, believes this could be the last time fans will see the five-year-old in Europe, and confirmed connections are looking at a trip to the Breeders’ Cup, should he run well.
He said: "It would be great to get his head in front this year and we’re all set to go.
"James Doyle obviously broke his hand, so that took him out of the equation. It’s great to have Colin Keane on board, he obviously knows Leopardstown well. Hopefully that will be to our advantage.
"I expect Vadeni to prove hard to beat, but I think a few people felt we were unlucky in the Eclipse, so let’s see what happens on Saturday.
"I suspect this will be the end of his season in Europe, so let’s hope he can go out on a high.
"We’ve talked about the Breeders’ Cup, but he would have to run well in Ireland to think about going there. If he was to win the Irish Champion, it’s a 'win and you’re in’ race.
"There’s the Champion Stakes at Ascot obviously, but if Baaeed goes there I don’t think we’d want to take him on again.
"As far as the Breeders’ Cup is concerned, I think he’ll be entered for the Turf and the Classic and we’ll see what’s in both races. Looking at Flightline the other day, I’d say the Turf would be the favoured option."
John and Thady Gosden, who train Mishriff in partnership, are keeping a watchful eye on the weather.
Gosden senior said: "His preparation has gone very well. They’ve had a lot of rain and we’ll see how much more rain they get.
"He can handle cut, but he wouldn’t want to see it going bottomless."
Grand Prix de Paris winner Onesto drops back two furlongs, while William Haggas relies on Tattersalls Gold Cup winner Alenquer, who has four and a half lengths to find on Vadeni from their Eclipse clash.
Aidan O’Brien has trained the winner of this race a record 10 times, including the last three renewals.
He saddles a trio, with Broome and Stone Age considered by bookmakers to be the lesser lights to Luxembourg, who was third in the 2000 Guineas before making a belated return to action in the Group Three Royal Whip at the Curragh.
Luxembourg’s jockey, Ryan Moore, expects to see improvement from the son of Camelot.
He said: "He obviously needs to improve on what he has done this year, but I think we’ll see a better version of him on Saturday, hopefully anyway.
"It was his first run for a while at the Curragh, yet he still pulled out at little bit more. He picked up very well, but he was just a bit idle in front. When the second horse came, he found plenty."
Auguste Rodin and Tower Of London give Aidan O'Brien a formidable hand in his bid for a ninth victory in the KPMG Champions Juvenile Stakes at Leopardstown on Saturday.
The master of Ballydoyle has saddled eight of the 15 previous winners of the Group Two contest, with Zoffany (2010), dual Derby winner Australia (2013) and Mogul (2019) among those on the roll of honour.
As the choice of jockey Ryan Moore, Auguste Rodin is the narrow favourite for this year’s renewal as he makes his first competitive appearance since scoring at Naas at the start of July.
His stablemate Tower Of London impressed on his racecourse introduction over the course and distance, with Moore in the saddle, and the leading rider feels both colts have big futures.
"They are two lovely horses," he said. "Tower Of London won his first start at Leopardstown very well although he was very green.
"August Rodin is a lovely Deep Impact colt. He got no run first time at the Curragh but came out and won at Naas. I expect he’ll improve from there."
With Moore aboard Auguste Rodin, Wayne Lordan comes in for the ride on Tower Of London.
Jim Bolger’s Serious Challenge, Donnacha O’Brien’s Alder and the Joseph O’Brien-trained Caroline Street are the other hopefuls.
The other Group Two on the card is the Clipper Logistics Boomerang Mile, in which Bolger’s Boundless Ocean bids to complete a Leopardstown hat-trick after winning the Meld and the Desmond Stakes.
His biggest threats appear to be Simon and Ed Crisford’s Celebration Mile winner Jadoomi and Just Beautiful, who makes her first start for Moyglare Stud Farm and trainer Paddy Twomey.
The latter has been off the track since winning the Group Three Sceptre Stakes at Doncaster 12 months ago for Ivan Furtado, since when she has changed hands for 625,000 guineas.
"We’ll find out a bit more about her," said Moyglare’s Fiona Craig. "Her best form is probably on fast ground, but we’ll find out on Saturday. She’s in very good order, so we’ll see."
Group Three honours are up for grabs in the Paddy Power Stakes, in which Point King bids to stretch his unbeaten record for the season to four for Joseph O’Brien.
Paddy Twomey’s pair of Beamish and Earl Of Tyrone and the Ger Lyons-trained Thunder Kiss are among those ready to take him on.
Dermot Weld's Homeless Songs has missed many opportunities since her startling Irish 1,000 Guineas success but she has been declared among a field of 11 for the Coolmore America 'Justify' Matron Stakes.
"I'm very pleased with her. She's had a long summer break," Weld told Ruby Walsh on RTÉ 2FM's Game On this week. "It's nice to have her. This is the start, really, of her autumn campaign."
"We'll probably look to include the Group One in France on Arc day and maybe all the way to the Breeders' Cup in November," Weld said.
"I'm delighted with her progress. What a wonderful summer we've had, but as a result the ground has been incredibly firm. She hasn't had the opportunity to work on grass - actually, once she's been on grass, to be quite honest. So I have her as forward as I can..."
She will not have it easy, though, with Jane Chapple-Hyam’s Saffron Beach, who has won the Duke of Cambridge Stakes and Prix Rothschild on her last two outings, heading the opposition.
O’Brien’s Tenebrism, winner of the Prix Jean Prat and second in the Rothschild, takes her chance along with Paddy Twomey’s Pearls Galore, the Sir Michael Stoute-trained Lights On and Joseph O’Brien’s Agartha.
Watch live coverage of Irish Champions Weekend from Leopardstown on Saturday on RTÉ2 and RTÉ Player from 2.30pm and from the Curragh on Sunday on RTÉ2 and RTÉ Player from 1.30pm.
