Willie Mullins' inmate did the business in a two-mile-one-furlong Connacht Hotel Handicap four days ago and repeated the dose in the hands of Declan McDonogh.
Sent off the 7-4 favourite in the feature race over a mile and a half, Whiskey Sour was patiently ridden by McDonogh as Mawaany went about his business at the top of the home straight.
Mawaany fought bravely, but Whiskey Sour was produced with a powerful drive on the grey's outside and won going away by three-quarters of a length.
Le Vagabond stayed on for third place, another six lengths in arrears.
Mullins said: "He was a bit keen early, but Declan was drawn on the outside and there was a strip of ground he wanted to go on.
"He loves Galway and I think his novice hurdling career is probably on hold for now.
"The English Cesarewitch is a race I'd like to think about towards the end of the season."
McDonogh added: "He was a bit gassy the first two or three furlongs - he just got going a little bit from a wide draw.
"I knew I had a bit of work to do, but he picked up really good.
"I could have done with a stronger pace, but it was a great performance from Willie to turn him around so quickly."
Mullins was on the mark for the eighth time at the 2017 Festival when Renneti (11-4 joint-favourite) took control of the Budweiser Race over a mile and three-quarters.
Riviera Sun (16-1) had earlier excelled in the Guinness Galway Blazers Handicap Chase.
Henry de Bromhead's eight-year-old, owned by JP McManus, gamely fended off Phil's Magic by three-quarters of a length in the hands of Barry Geraghty.
Net D'Ecosse finished third, while The Gatechecker was fourth.
De Bromhead was winning the race for a second consecutive year after striking last season with On Fiddlers Green, who was never a factor on this occasion.
He said: "He had that soft-ground form, which was great, and it was a super ride from Barry. He was brilliant, but we'll enjoy this and see what's next.
"I suppose we can look at a Munster National or a Kerry National. I don't know whether he's rated high enough for that but we'll see.
"On Fiddlers Green disappointed but I think he just hated the ground."
Brendan Duke has high hopes for Warm The Voice after the 2-1 favourite won the seven-furlong maiden by two and three-quarter lengths from Shifted Strategy.
Duke said: "First of all he's special - that's the first thing. He's an absolutely proper horse.
"Ground would have been a real problem for him but he's just very good. I'd be inclined to go steady away until next year but he is a stakes horse."
Conor O'Dwyer landed a first Galway winner as a trainer when Flaming Sea delivered in the mile-and-a-half fillies' maiden by half a length from Flaming Sea.
O'Dwyer said: "She's a seriously well-bred mare. I don't know whether they (her owners) want to go breeding with her or to get a bit of black type, but that win was important."