French Open victor Jelena Ostapenko struggled at times before beating Duan Yingying 6-3, 3-6, 6-4.
Sensational Martha Kostiuk at the age of 15, will play in the third round of the adult tournament series Grand slam.
Perhaps an even tougher challenge, she followed that up with a convincing win over Australian wild-card entry Rogowska in front of a partisan crowd at Margaret Court Arena on Wednesday.
Another of Tsonga's array of shots during the final set included one from between his legs for a victor.
Fett is ranked 119th and was making her first appearance in the main singles draw of a Grand Slam tournament.
Argenutina's Leonardo Mayer gave Nadal a real game and broke the Spaniard when he was serving for the match before forcing a third-set tiebreak.
The Ukrainian is now on a seven-match win streak after winning the lead-up Brisbane International.
Andreas Seppi beat Yoshihito Nishioka 6-1, 6-3, 6-4.
Nadal, showing no signs of the troublesome knee that bothered him late last season and interrupted his Melbourne lead-up, next plays Bosnian 28th seed Damir Dzumhur.
"When you win one, two matches, everybody focuses on you", said Bencic, who has since struggled with injuries and lost her second-round match at the Australian Open only two days after an upset win over Venus Williams. She's never advanced beyond the third round, however.
The Ukrainian is now on a seven-match win streak and after picking up five WTA Tour titles previous year, more than any other woman, is a serious Grand Slam contender. She beat two top-10 players to take the trophy.
Marta Kostyuk, the 15-year-old Ukrainian qualifier, became the youngest player to reach the third round of the Australian Open since Martina Hingis in 1996. And that came after three three-set matches in qualifying over six hours.
The Australian Open junior champion past year, who entered the season-opening major ranked No. 521, Kostyuk became the youngest player since Martina Hingis in 1996 to win main draw matches at the season-opening major.
Australian Open is already a very special place for Marta Kostyuk. Gavrilova made the semifinals in Sydney last week and is a plucky sort who won't give an inch, but Mertens is playing well and I think she will once again send Gavrilova crashing out of a Slam.
"Definitely wasn't a good day at the office", a visibly emotional Rogowska said, dubbing the defeat against the grand slam newbie one of the most disappointing of her career.
In what shapes as an entertaining showdown, he'll meet No. 17-seeded Nick Kyrgios in the next round.