The in-form 21-year-old Australian, who came through two rounds of qualifying in Florida before upsetting Czech Sara Bejlek, Japan's four-time slam winner Naomi Osaka and American teen sensation Iva Jovic in the main draw, suffered a 6-2 6-2 loss in her last-16 clash with Kazakh Rybakina.
The Perth product, who last week reached the quarter-finals at Indian Wells, was broken in the opening game and once more in the seventh to drop the first set.
Gibson came up short on serve again at 2-2 and 4-2 down in the second set and 2024 and 2025 Miami runner-up Rybakina, who faced only one break point in the entire contest, and saved it, booked her place in the last eight after just 62 minutes.
World No.1 Aryna Sabalenka and fifth seed Jessica Pegula also cruised to straight-sets wins. The Belarusian beat Zheng Qinwen 6-3 6-4 while the American downed Jaqueline Cristian 6-4 6-1.
Earlier on Monday (Tuesday AEDT), Victoria Mboko gained some revenge for her loss in the final of the Adelaide International to fellow teenager Mirra Andreeva.
Canada's 19-year-old world No.9 raced through the final set to defeat Andreeva, Russia's 18-year-old eighth seed, 6-7 (7-4) 6-4 6-0.
In the quarters, 10th-seeded Mboko will have another shot at revenge as she faces Czech Karolina Muchova, who beat her in the Qatar decider last month.
Muchova, the 13th seed, defeated another young gun in 20-year-old Philippines world No.29 Alexandra Eala, 6-0 6-2.
Fourth seed and 2023 US Open and 2025 French Open winner Coco Gauff outlasted Sorana Cirstea 6-4 3-6 6-2 to set up a last-eight match with Belinda Bencic, a 6-2 6-2 winner over sixth seed Amanda Asimova.
Meanwhile, world No.3 Iga Swiatek has ended her coaching partnership with Wim Fissette, following a disappointing start to the season that culminated in a shock early exit in Florida.
The 24-year-old, who hired the Belgian in October 2024, said she had decided to take a different path after a 17-month stint that included her maiden Wimbledon title last year. However, Thursday's loss to world No.50 and Polish compatriot Magda Linette proved a turning point for the six-time grand slam winner.
"Miami was challenging for me. I feel disappointment, bitterness and responsibility for my performance on the court," Swiatek wrote in a social media post.
"I'm grateful for (Fissette's) support, experience, and everything we achieved together, including one of my biggest dreams in sport."
With Reuters
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