Swiatek keeps nerve to fight past Noskova, Gauff advances in Miami
A day after Swiatek's closest challenger, Aryna Sabalenka, was knocked out of the tournament, the Pole faced a real test from Noskova.
The Czech had upset Swiatek in the third round of the Australian Open before the four-time Grand Slam winner gained revenge at Indian Wells.
The third meeting this year between the pair was, not surprisingly, a tight affair.
Having worked hard to recover from her opening set tie-break loss and taken the match into a deciding frame, Swiatek found herself facing three break points when serving for the match up 5-4.
But she stepped up her game to win the next five points and celebrated with a fist-pumping gesture to her box.
Swiatek will face 14th seed Ekaterina Alexandrova in the round of 16 on Monday. Alexandrova went through with a 6-4, 3-6, 6-3 win over fellow Russian Anastasia Pavlyuchenkova.
France's Caroline Garcia progressed to a fourth-round match against world number three Coco Gauff with a 7-6 (7/4), 7-5 win Sunday over Naomi Osaka.
It was a hard-hitting match with the pair sharing 28 aces and Osaka had to fight to take the first set to a tie-break, saving three set points.
Garcia secured the tie-break with forehand winner, but found herself trailing Osaka 4-2 in the second before breaking back.
With Osaka serving at 5-all, Garcia forced two break points, converting the second.
Reigning US Open champion Gauff was down 4-2 in the first set to France's Oceane Dodin before winning 10 straight games and running out a 6-4, 6-0 winner.
Gauff said she expected a difficult game against Garcia.
"She's tough. We all know how she plays. Takes the ball super early, plays very aggressive," she said.
Fifth-seeded American Jessica Pegula beat Canada's Leylah Fernandez 7-5, 6-4 to set up a fourth round clash with in-form compatriot Emma Navarro.
Fernandez broke to take a 5-3 lead in the first set but Pegula responded perfectly, winning four straight games to take the set, bringing spectators to their feet with a backhand winner down the line to clinch the set.
Both players struggled to hold serve in the second set, with the first seven games going against serve, but Pegula finally held to go 5-3 up and she held the final game to love to secure the win.
Pegula to play Navarro
Pegula, the highest-ranked American woman, will play against the rising star of USA women's tennis in Navarro, who upset 12th-seeded Italian Jasmine Paolini 6-2, 3-6, 6-0.
Paolini, who won the WTA 1000 Series event in Dubai earlier this year, faded after fighting back in the second set while Navarro confirmed her status as one of the most improved players on the tour.
With her 20th match win of the season, a record bettered only by Swiatek, Navarro is enjoying the most successful campaign of her career, having won her first WTA title in Hobart in January.
Pegula said the belief that comes from such a run of results will make her a difficult opponent.
"That feeling of winning a lot of matches, it's really tough to beat people like that and even if you do beat them it's never easy," she said.
"It will be a really good test for me to see where I'm at considering she is probably one of the hottest players on tour right now."
The 20th seed's rise has impressed Gauff.
"I'm not surprised by her being top 20, honestly. I would say (more) maybe how fast, it happened so fast. But when we played in juniors, she's always had an all-around game.
"She's a great athlete. She's a very smart player, she's giving the top players trouble. She's not somebody you want to see early in the tournament," Gauff said.