"I've never played her before. She's a tricky opponent. She had nothing to lose."
Fett twice faltered when serving for the match and a place in a grand slam third round for the first time after Wozniacki fell foul of the chair umpire for a second time early in the third set.
The Dane was fuming after having a point contentiously replayed before dropping serve to hand Fett a break and a 2-1 lead.
"Oh, so you're giving her the benefit of the doubt, but you're not giving it to me?" she asked British official Richard Haigh before dumping a volley into the net, then thrashing her racquet into the court in disgust after dropping serve.
The incident came after Haigh denied the former world No1 a challenge for taking too long during her second-set fightback, much to Wozniacki's disgust.
"What are you talking about? I'm hitting two hands on the backhand. What do you want me to do? Like, hit it one hand and shout," she quizzed Haigh.
But the steadfast official was having none of it.
"You need to be faster. You can't wait until that one bounces and then say challenge. I told you at the pre-match meeting to use your voice and not just lift your arm," he fired back. "You waited to see the result of your shot then you said challenge."
Wozniacki retained her composure to win the second set and level the match, but it wasn't long before she came under the gun again as Fett threatened to pull off what would have been the boilover of the Open.
French Open champion Jelena Ostapenko made the third round, beating Duan Yingying 6-3 3-6 6-4 on Margaret Court Arena, progressing to the third round for the second year in a row.
Comebacks were the order of the day as Jo-Wilfred Tsonga fought back from 2-5 down in the fifth set against Canadian teenager Denis Shapovalov.
Tsonga came back from the brink of elimination as Shapovalov faltered in the final set with victory within his grasp.
The energetic Frenchman won 3-6 6-3 1-6 7-6 7-5 and now advances to the third round.
For the 18-year-old the loss will sting for a long time but one that should teach him plenty of lessons for the future.
Shapovalov had the advantage in the fifth set and was seemingly set for a landmark win. Shapovalov tightened, however, and Tsonga pounced, reeling off five straight games to take the match and a third round berth.
"Of course I'm tired but really happy. I did a big fight today," he said.
"It's not easy to play against the young guns. They go for everything. It's not easy for me to defend," said Tsonga.
"It was really difficult for me because I struggle physically."
The athletic Shapovalov, often compared with a younger Tsonga, had a few great moments of his own, including a shot around the net from the baseline for a winner.
"There's always nerves in a tennis match," Shapovalov said of the blown fifth-set lead. "I wasn't thinking about it much. Just didn't play a good game on my serve. Then he picked up his level. I'm just going to learn from it and keep going."
●New Zealand doubles player Artem Sitak kick-started his Australian Open campaign with a comfortable first-up win.
Sitak and Dutch partner Wesley Koolhof breezed into the second round after crushing the Germans Peter Gojowczyk and Florian Mayer 6-2 6-1 in just 49 minutes.
They will face a stern test in the second round against seventh seeds Oliver Marach and Mate Pavic.
The Austrian-Croatian combination have started the year in superb fashion, winning the titles in Doha and Auckland's ASB Classic.
The other Kiwis in the draw, Michael Venus and Marcus Daniell, are likely to play their first round matches today. Venus and Raven Klaasen (South Africa) are seeded eighth and play Scott Lipsky (US) and Spaniard David Marrero.
Daniell and his partner Dominic Inglot (Britain) play Adil Shamasdin, of Canada, and Britain's Neal Skupski in the first round.
