Jessica Pegula returns to Katherine Sebov (not in photograph) of Canada during the Miami Open tennis tournament, on March 23, 2023, in Miami Gardens, Florida. (PHOTO / AP)

Americans Jessica Pegula and Coco Gauff secured straight-sets victories over Canadians on Thursday to book their spots in the third round of the Miami Open.

Third seed Pegula beat qualifier Katherine Sebov 6-3 6-1 and will next face fellow American Danielle Collins while sixth seed Gauff eased past Rebecca Marino 6-4 6-3 to set up a battle with Russia's Anastasia Potapova.

Pegula, a semi-finalist last year in Miami who lives about 40 minutes away from the tournament venue, converted five of her nine break point opportunities and found her groove as her first career match against Sebov wore on.

Jessica Pegula opened the match with a break but Katherine Sebov broke back at love to level at 2-2 before the American took control with another break for a 3-2 lead and closed out the first set in 35 minutes

"I just went out the and took care of business ... fought through some tricky moments in the first set but then I think I started to free up after that," Pegula said in her on-court interview.

Pegula opened the match with a break but Sebov broke back at love to level at 2-2 before the American took control with another break for a 3-2 lead and closed out the first set in 35 minutes.

The 29-year-old Pegula had a much easier time in the second set where she broke early for a 2-0 lead and dropped just two points on serve the rest of the way.

Gauff, who resides in Southeast Florida and is coming off a run to the quarter-finals in Indian Wells, also converted five of her nine break point chances and twice came back from a break down in the second set.

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"Playing at home is something I look forward to but it's also a little extra pressure because you know everybody wants you to do well here." said Gauff.

With the victory, the 19-year-old Gauff broke a stalemate with Anastasia Pavlyuchenkova and now holds the record for most wins (34) at WTA 1000 events before turning 20.

Coco Gauff of the US prepares to return serve against Rebecca Marino (not pictured) of Canada on day four of the Miami Open at Hard Rock Stadium on March 23, 2023 in Miami, Florida. (PHOTO / GEOFF BURKE-USA TODAY SPORTS VIA REUTERS)

In other second-round action, Belgian Elise Mertens beat Russian eighth seed Daria Kasatkina while Latvian 24th seed Jelena Ostapenko, Spanish 21st seed Paula Badosa and China's Zheng Qinwen, the 23rd seed, also advanced.

With the victory over Rebecca Marino, Coco Gauff, 19, broke a stalemate with Anastasia Pavlyuchenkova and now holds the record for most wins (34) at WTA 1000 events before turning 20

Wimbledon champion Elena Rybakina, fresh off her triumph at Indian Wells, will close out the evening session when she faces Russia's Anna Kalinskaya for a spot in the third round.

If Rybakina lifts the title in Miami, she would become only the fifth woman to win the Indian Wells and Miami tournaments back-to-back, a feat known as the "Sunshine Double" given the tournaments' locations in California and Florida.

On the men's side, Chilean qualifier Cristian Garin, who made a surprising run to the fourth round at Indian Wells, beat Marcos Giron 6-2 2-6 6-4 to reach the second round in Miami.

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Austrian wildcard Dominic Thiem will kick off the evening session with a first-round clash against Italy's Lorenzo Sonego while Frenchman Richard Gasquet battles Australian lucky loser Christopher O'Connell.