Tennis: Influencer Morgan Riddle makes good on Vegemite dare, as boyfriend Taylor Fritz advances to Australian Open quarter-finals

American social media influencer Morgan Riddle has reluctantly delivered on her Vegemite promise, after boyfriend Taylor Fritz progressed to the Australian Open quarter-finals at Melbourne.

Riddle, 26, has been a constant courtside presence during Fritz's progress through the year's first Grand Slam, urging her man towards a showdown with 10-time champion Novak Djokovic in the final eight.

The 12th seed overcame seventh-seeded Greek Stefanos Tsitsipas in the fourth round and immediately called on his better half to fulfill her pledge to eat a jar of the traditional Australian delicacy, if he prevailed.

"I told them I was going to win," admitted Fritz. "My girlfriend thought I was too confident going into the match."

Fritz admits he has tried the leftover brewers yeast and "wasn't the biggest fan".

Within 24 hours, Riddle sampled the breakfast spread with a teaspoon live on Instagram, gagging, before supposedly regurgitating it off camera.

"What the f***!" she declared. "That was disgusting."

Vegemite producer Bega Cheese has responded to the stunt.

"@moorrgs, if you're going to do it, at least do it right," it posed on the official Vegemite Instagram page. "Australia, thoughts?"

Riddle was bombarded with suggestions to make her tasting experience a little more pleasant.

Maybe she will be a little more careful about her promises, when Fritz takes on top seed Djokovic on Tuesday.