Marta Kostyuk came from the other angle, the 15-year-old qualifier followed up her first-round win over 25th-seeded Peng Shuai with a 6-3, 7-5 victory over wild-card entry Olivia Rogowska.
He improves his head-to-head record against Mayer to 5-0, but he was obviously wary of the threat his opponent provided having dropped the opening set to him in the last 32 before winning in four sets on his way to claiming the US Open past year.
But Mayer would not go down without a fight.
The 31-year-old Bondarenko broke Pavlyuchenkova's serve four times and only dropped her own serve once to register her 20th career win against a top 20 player.
The 2.11 metre Karlovic finally got the decisive break in the fifth set in the 21st game and held firm to complete victory with a nerveless backhand volley.
The issues came with a freakish series of disruptions off-court, that saw a helicopter halt play, a heckler in the crowd get ejected from the venue after shouting and a problem with the arena's audio speakers that caused feedback issues for both players. Neither player was having trouble on their serve until Mayer was having slight problems on his serve.
Numerous top seeds at the Australian Open tennis tournament struggled through their second round matches here on Wednesday, as young guns put on a show for the 70,000 fans in attendance at Melbourne Park.
EPARafa Nadal is Greg Rusedski's tip to reach the final
The world number one was looking to pounce early to try and close it out, but the Argentine was not going to make life easy for him.
Nadal would go break point down in the next service game but went with a classic tactic to save it. The Spaniard kept it on serve at three-all.
Kyrgios dominated the first set but had to wait until the 11th game to break, before serving out the set.
It was a powerful performance from the 16-time grand slam champion, who conceded only 10 unforced errors, stacked up against his 40 winners. Siniakova had to work a lot harder for her first-round win here, though: she lost the first set to Greece's Maria Sakkari but then secured the second set in the tie-break and won the third set quite comfortably.
Wozniacki was 5-1 down and facing two match points in third set against No. 119-ranked Jana Fett before deciding she had no choice but to attack.
An animated Nadal leapt into the air and pumped his fist with delight after sending a searing forehand victor down the line to go up 4-2 before serving out the match.
Karlovic, 39 next month, served down 53 aces as he came through 7-6 (7-3) 6-7 (3-7) 7-5 4-6 12-10 in four hours and 33 minutes - the longest match in the tournament so far.