Angelique Kerber and Garbine Muguruza made it to the third round of the Miami Open on Friday but Venus Williams suffered an early exit.
Second seed Kerber eased through her match against Barbora Strycova 6-1 6-1, while fourth seed Muguruza battled from behind to complete a 6-7 (3-7) 6-3 7-5 victory against Dominika Cibulkova.
Qualifier Elena Vesnina knocked out Williams, a three-time winner in Florida, with a dominant 6-0 6-7 (5-7) 6-2 win.
It was a mixed day for the rest of the seeds as Carla Suarez Navarro was eliminated by Coco Vandeweghe, while Victoria Azarenka and Roberta Vinci advanced into the last 32.
KERBER DOMINATES, MUGURUZA BATTLES
After her surprise exit at Indian Wells, Kerber opened her Miami Open in superb fashion with a dominant victory over Strycova.
The 28-year-old German needed just over an hour to complete a straight-sets victory, breaking six times to ease past her Czech opponent.
The win was Kerber's second since her Australian Open triumph, following a victory over Timea Bacsinszky in the Fed Cup last month.
Muguruza's match was not as comfortable, as the Spaniard had to fight from a set down to get past Cibulkova.
The contest went for two hours, 46 minutes before Muguruza completed the victory to send her to the third round.
TOUGH DAY FOR THE SEEDS
Nine seeds were knocked out of the Miami Open on Friday, with sixth seed Suarez Navarro the highest to go.
The Spaniard, last year's runner up, went out to American Vandeweghe in straight sets, broken three times in the 6-4 6-2 loss.
Suarez Navarro was joined by Williams, along with seventh seed Belinda Bencic and Sara Errani, the latter ousted by wildcard Naomi Osaka.
Other seeds to depart were Karolina Pliskova, Anastasia Pavlyuchenkova, Sabine Lisicki, Kristina Mladenovic and Jelena Jankovic.
BENCIC, JANKOVIC RETIRE
Both Bencic and Jankovic failed to complete their first sets before retiring against Kristyna Pliskova and Magda Linette respectively.
A lower back injury forced Bencic to retire while 4-1 down in the first set, while Jankovic failed to make it past five points due to a shoulder problem.
VENUS CREDITS VESNINA
Williams was full of praise for the unseeded Vesnina, saying: "I didn't get a chance to play as much offense as I would like, but just credit to [Vesnina] for playing well. Hopefully, she can keep that level throughout the whole tournament.
"What else can you do except try to stay focused on the task at hand? It was definitely a physical match. [Vesnina] played amazing tennis. All credit to her today."
SERENA BACK IN ACTION
Serena Williams will be looking to qualify for the last 16 when she fronts Zarina Diyas on Saturday.
Simona Halep is in action against Julia Goerges, while third seed Agnieszka Radwanska faces Madison Brengle.