Coco Gauff eases into third round of Miami Open

The number six seed defeated her Canadian opponent 6-4 6-3 in the second round in an hour and 12 minutes, after celebrating her 19th birthday just the week before.

Ukrainian Marta Kostyuk refused to shake hands with Russian opponent Anastasia Potapova, after she was beaten in two sets.

Potapova won 6-1 6-3, a week after she received a formal warning from the WTA for wearing a Spartak Moscow football shirt at Indian Wells last week.

Jessica Pegula eased through to the third round with a 6-3 6-1 win over Canadian qualifier Katherine Sebov.

"I luckily knew her a bit," said the victorious American afterwards, reported by the WTA website.

"We were playing [ITF events] around the same time, and she's been doing much better this year, starting to creep back up there and playing some good tennis."

Fellow United States player Danielle Collins will be Pegula's opponent in the next round after she beat Viktoriya Tomova 7-6(3) 6-2.

Elise Mertens was the surprise of the round, coming from behind to knock out number eight seed Daria Kasatkina.

Mertens lost the first set 6-4 but came back to take the next two 6-2 6-2 and win the match.

Wimbledon champion Elena Rybakina, fresh from her triumph in Indian Wells, needed three sets to see off Anna Kalinskaya 7-5 4-6 6-3.

The number 10 seed will play Paula Badosa, seeded 21, who beat Laura Siegemund.

Three-time champion Victoria Azarenka, seeded 14, booked a third-round meeting with number 20 seed Magda Linette by beating Camila Georgi 6-3 6-1, while Jelena Ostapenko beat Mirjam Bjorklund 6-3 6-4.

Number 13 seed Beatriz Haddad Maia and Zheng Qinwen also went through after beating Tereza Martincova and Irina-Camelia Begu respectively.