Top-ranked Iga Swiatek escaped with a narrow 6-4, 3-6, 6-4 win over 2022 runner-up Collins to advance to the third round of the Australian Open on Thursday.
Swiatek was up a set and a break before the American player rallied to take the second set and race to a 4-1 lead in the third.
Swiatek absorbed the sustained pressure from Collins’ powerful groundstrokes until she regained momentum and went on a match-winning five-game roll.
Meanwhile, another upset was on the cards in Melbourne.
France's Clara Burel stunned No.5 seed Jessica Pegula of the United States 6-4, 6-2 on Thursday to claim the the first Top 10 win of her career and advance to the third round of the Australian Open.
The 51st-ranked Burel needed only 70 minutes to knock out the 2023 Australian Open quarter-finalist Pegula.
In Men's Singles, Olympic champion Alexander Zverev held off Lukas Klein 7-5, 3-6, 4-6, 7-6 (5), 7-6 (7) in 4 1/2 hours to reach the third round at the Australian Open
No.11 seed Casper Ruud moved to the third round of Australian Open after he defeated local player Max Purcell 6-3, 6-7 (5), 6-3, 3-6, 7-6 (7)
World No. 2 Carlos Alcaraz conceded the second set but eventually prevailed over Lorenzo Sonego 6-4, 6-7 (3), 6-3, 7-6 (3) to reach the third round of the Australian Open for the second time.