Naomi Osaka is through to the third round of the Miami Open after beating former world number one Angelique Kerber in straight sets.

Osaka won the first three games of the match to jump out to an early lead, securing the set with a double-break before breaking early in the second to cruise to a 6-2 6-3 win.

The story of the match was Osaka's ease in winning points against Kerber's serve, winning 41 per cent (15/37) of Kerber's successful first serves, while the German could only win 11 per cent (3/27) in the same category.

Britain's top-ranked woman Emma Raducanu suffered another early exit, on the wrong end of Katerina Siniakova's comeback 3-6 6-4 7-5 win.

Raducanu was more than solid in the first set, producing 10 break points and capitalising on two, but Siniakova won a higher percentage of both service points and return points than her British counterpart in the second and third sets, earning the result.

America's Danielle Collins and Hungary's Anna Bondar contested the closest match from the early session, with the former prevailing 6-3 3-6 6-4.

Meanwhile, top seed Aryna Sabalenka is out after a surprise loss to 31-year-old Romanian Irina-Camelia Begu, going down 6-4 6-4.

Sabalenka's serve betrayed her in the match, with four double faults in each set, while Begu won the only break point opportunity in the opener and saved all five chances for Sabalenka to break back in the second.

Anna Kalinskaya notched one of the best wins of her young career, taking out world number eight Karolina Pliskova 6-3 6-3. Pliskova finished with nine double faults, while Kalinskaya only had one.

American 21-year-old Ann Li made a statement with her win over world number seven Anett Kontaveit, storming through the first set in just 23 minutes on the way to a 6-0 3-6 6-4 win.

Belinda Bencic was strong in her contest against Ukrainian Marta Kostyuk, facing zero break points on the way to a 6-3 6-1 win.

World number 10 Ons Jabeur survived a set point in her first set against Magda Linette before ultimately dominating the tie-break and the second set, winning 7-6 (7-1) 6-1.

After former world number one Simona Halep withdrew due to injury, Daria Saville played French replacement Harmony Tan, winning comfortably 6-4 6-2.

Exciting young Canadian Leylah Fernandez was bundled out in straight sets by Czech Karolina Muchova 6-4 7-6 (7-3). With her win, Muchova will play Osaka in the third round.