Venus Williams fought back from a set down to end Johanna Kontas defence of her Miami Open to advance to the quarter-finals.
The American was dumped out in the semi-finals by the Brit in 2017 but exacted her revenge in style to move into the last-eight with a 5-7 6-1 6-2 win in two hours and 20 minutes.
Konta, who struggled with a back issue in the latter stages of the contest, had been in impressive form in the build-up to the clash with the world No. 8 but after a bright start, the defending champion fell away.
The defeat will see her drop outside the top-20 for the first time since May 2016 and continues a largely disappointing start to this season.
Though Konta beat the eighth seed on her way to the title in Florida last year, she had since lost to Williams in Rome and Wimbledon as part of a tight 3-3 head-to-head.
Konta got off to the perfect start, breaking Williams in the opening game.
After holding to love, the Brit continued to turn the screw, creating four break point chances in a marathon third game, but the experienced American held firm to get on the board.
Recent Miami Open champions (WTA)
2015: S. Williams
2014: S. Williams
2013: S. Williams
2008: S. Williams
Williams began to find her rhythm and broke the British No. 1 back to level at 3-3.
When 5-4 up Williams forced a set point on the Konta serve but the 26-year-old battled through before breaking the seven-time Grand Slam champion to take a one-set lead.
Once again, the 37-year-old found her composure at the start of the second, breaking for a 2-0 lead.
As Williams stormed to a 6-1 second set to set up a decider, Konta called out the trainer, seemingly struggling with her lower back.
The Brit was broken at the beginning of the third but and though she quickly levelled at 2-2, Williams reeled off the next four games to book her spot in the next round.
American qualifier Danielle Collins will take on Olympic gold medal winner Monica Puig later in the day to determine who Williams next opponent will be.
Earlier on Monday, Garbine Muguruza was taken out 6-3 6-4 by US Open champion Sloane Stephens and she will face Angelique Kerber in the last-eight after the German fought back from a set down to beat Chinas Wang Yafan 6-7 7-6 6-3.
Fifth seed Karolina Pliskova advanced as Zarina Diyas retired when 6-2 2-1 down and she will take on three-time champion Victoria Azarenka, who beat Agnieszka Radwanska 6-2 6-2, with Elina Svitolina also booking her spot in the quarter-finals with a 7-5 6-4 win over Ash Barty.
On the mens side of the draw, Nick Kyrgios eased past volatile Italian Fabio Fognini, with young Canadian booking his spot in the last-16 with a terrific win over Americas Sam Querrey.
Milos Raonic, Pablo Carreno-Busta and Milos Raonic also moved into round four.