Gauff's victory snapped the 11-match winning streak of Pliskova, a former World No. 1. Two weeks ago, Pliskova won at Cluj-Napoca for her first title since 2020 and has risen from No. 78 to No. 36 in the rankings.
The American teen's victory came in one hour, 53 minutes, and she now has won two of three head-to-head matches against Pliskova.
"I feel like (Pliskova's) been playing well since the start of the year, coming back from injury," Gauff said after the match. "Even though her ranking is probably not where it should be considering the calibre of player she is, I think it definitely felt like a top win for me. Hopefully I can continue to use that to build my confidence going into the rest of this week."
Gauff now has reached at least the quarterfinals in three of her four entries in Dubai and will be playing in her third quarterfinal of 2024 when she meets Russian qualifier Anna Kalinskaya. It will be Gauff's first clash with Kalinskaya, ranked No. 40.
Kalinskaya upset No. 9 seed Jelena Ostapenko of Latvia 6-4, 7-5 on Wednesday in 93 minutes. It was just the fourth loss of the season for Ostapenko, who has 16 match wins, trailing only Elena Rybakina of Kazakhstan.
Rybakina, the No. 4 seed, notched another victory when she came from 5-3 down in the first set to defeat Polish qualifier Magdalena Frech 7-6(5), 3-6, 6-4 in two hours, 39 minutes. She is now 17-3 on the season.
Rybakina has won 10 out of 11 matches on the WTA Tour's swing through the Middle East. She won the tournament two weeks ago in Abu Dhabi and lost to World No. 1 Iga Swiatek in the final in Doha last week.
Next up for Rybakina is Italy's Jasmine Paolini, who upset No. 8 seed Maria Sakkari of Greece 6-4, 6-2.
Rybakina admitted her strong play in the Middle East has left her tired as she readies to play Paolini on a short turnaround.
"It's a good problem to have," Rybakina said. "No one expected me to play so many matches in the past two weeks. I think it's already good what I'm doing. Whatever happens this week, I know that there is other tournaments in front. I'm not a machine that can work every day the same in the end of the day."
Also on Wednesday, Swiatek recorded a 6-1, 6-4 victory over 15th-seeded Elina Svitolina of the Ukraine.
In other action, Czech Marketa Vondrousova, the No. 7 seed, defeated No.12 seed Liudmila Samsonova of Russia 6-2, 6-2 in 75 minutes. Awaiting her in the quarterfinal is Romania's Sorana Cirstea, who defeated Croatian Donna Vekic 3-6, 6-3, 7-5.
