Graham Whelan, 46, of Altona, spent three weeks building a Melbourne Cup playlist of horse-themed songs for his backyard party on Tuesday, and he would like it noted that none of it was a joke.

"It's the Cup," he said. "It's a horse race. I made a playlist about horses. I don't know what the confusion is."

The confusion, according to the seventeen guests who attended, began at 11:40am when the opening track, Pink Pony Club, was followed by Horses, then Buy Me a Pony, then a song about a man on a horse with no name, then Wild Horses, then Old Town Road, and then Pink Pony Club again, which Mr Whelan described as "bringing it back around."

"Everyone was waiting for him to say he was kidding," said Jodie Brennan, a neighbour who brought a platter of sausage rolls. "That moment where he looks at you and grins. It never came. By one o'clock we'd all worked out it wasn't coming."

Mr Whelan built the playlist in a spreadsheet, with columns titled Pony Count, Gallop Tempo, Mane Mood, Hoof Content, and Suitable For Hat Judging. Wild Horses is timed to begin at 2:58pm as the field enters the barriers, a decision he said "took some thinking." He tested the timing on three separate evenings and rehearsed a short speech about the hat competition that guests did not realise was scheduled until it began.

Guests, who were at first going along with it for a laugh, drifted into meaning it at around 2pm, when a man who had arrived planning to keep a straight face was caught singing the second verse of Horses with his eyes closed.

"I don't know what happened," the man said. "Somewhere around the third pony song I just started to feel it."

By the time the race ran, the backyard had gone quiet. Mr Whelan's sweep winner, a woman who drew the horse by chance and had not looked at the form, collected $68 to Old Town Road, which she described as "oddly appropriate."

Three guests have since asked for a link to the playlist. Mr Whelan's partner, Sandra, then admitted that she had been adding songs to the spreadsheet over the three weeks, including Buy Me a Pony and the second Pink Pony Club, and that he had assumed he'd picked them himself.

"He never noticed," she said. "The Pony Count column just kept going up and he kept being pleased about it."

Mr Whelan said he had no recollection of that, but that both songs "fit the brief."