The Andre Fabre-trained duo crossed the line in unison, with the front-running Thunder Snow narrowly behind them, but it was Frankie Dettori's mount who got the verdict.
Inns Of Court was an extremely unlucky loser as he reared leaving the stalls, costing him a couple of lengths, and was in front just before the line and immediately after it.
Saeed bin Suroor's Thunder Snow tried to steal the race from the front under Christophe Soumillon and with half a furlong to go it appeared as if he had.
However, while Al Wukair was struggling to get to him, Inns Of Court went past on the far side before Dettori managed to get his mount in front right on the line.
Third in the 2000 Guineas at Newmarket to Churchill, Al Wukair has only been seen once since, when behind Taareef at Maisons-Laffitte but he turned that form on its head.
Thunder Snow made a bold bid from the front to add to his Prix Jean Prat success, but ultimately he had no answer to the late thrusts of the Fabre duo.
Dettori - standing in for the injured Gregory Benoist - told At The Races: "He jumped a lot more alert than last time and the pace of the race was slow.
"Andre said to me to try and build it up as he doesn't do anything quick so I decided to attack Christophe (Soumillon, on Thunder Snow) about two and a half out.
"He was playing around a bit, though, and looking around, so I had to get a bit serious with him and then when Mickael (Barzalona, on Inns Of Court) came alongside he felt it was time to go.
"He got a crack off Christophe's whip in his face and I think that woke him up and we flashed past the line together. I wasn't sure I'd won, but it's a great win and he's a good horse. The Jacques le Marois is one of the best races in Europe."
He added: "Obviously the rain helped, I rode him on firm in the summer and he didn't really like that.
"I guess the long-term plan will be the QEII (at Ascot) where he is guaranteed to get softer ground and he likes to go straight.
"A mile and a quarter is within his compass too, and at some stage we'll look at stepping him up."
Fabre, however, suggested a step up in trip for the Champion Stakes could be the order of the day.
He said: "Al Wukair could go to Ascot over 2,000 metres (10 furlongs). I would like to say a word about Gregory Benoist. He had ridden the horse wonderfully in the past and I wish him a quick recovery."
Rupert Pritchard-Gordon, representing owners Al Shaqab Racing, said: "After his very good race in the Guineas, it is very nice to see him do this. The softer ground was not a problem.
"We could step him up in trip - the Champion Stakes has been mentioned."
Just 24 hours on from riding his 2,000th winner in Britain, Jamie Spencer was seen to great effect in France.
Riding God Given for his old boss Luca Cumani in the Group Three Prix Minerve, he made all to run out a comfortable winner.
Winner of a Listed race at Newmarket last time out, the half-sister to the top-class Postponed handled the step up in grade with aplomb.
Dettori briefly threatened on John Gosden's Elas Ruby but she faded to third as Calayana and Lady Montdore claimed minor honours.
Cumani said: "There was no obvious pace in the race so we thought we'd allow her to use her stamina.
"She's a filly I have always liked and we have now managed to work our way up and win a Group Three.
"A bit like her half-brother she should get better with time. She doesn't need soft ground and it maybe just inconveniences her rivals more than her, but at home she is a beautifully-actioned filly.
"The big target has always been the Fillies And Mares' race on Champions Day and she'll need another run in between so we could possibly come back to France for the Prix Vermeille at Chantilly."
Spencer had earlier ridden his rivals to sleep when stepping into the plate on Mythical Magic in the Prix Francois Boutin.
Replacing William Buick, who was hurt in the fatal fall of Permian in America on Saturday night, Spencer yet again confounded those who pigeon hole him as a hold-up jockey.
Winner of his only start at Ascot, the son of Iffraaj relished the soft ground and held off fellow Godolphin runner Cascadian, after Fabre's runner was very slowly away.
Trained by Charlie Appleby, Mythical Magic holds entries in the Gimcrack at York and the Champagne Stakes at Doncaster.