A pair of Americans were responsible for a pair of upsets on both the men's and women's sides of the Miami Open on Sunday, with No. 29 Jessica Pegula downing No. 6 Karolina Pliskova and No. 18 John Inser beating No. 11 Felix Auger-Aliassime in a stunner.

Both players advanced out of the round of 32 to highlight Sunday's early matches, while Naomi Osaka moved on as well after Nina Stojanovic withdrew with an injury, but there are still several matches to come.

Check back here for results and highlights from the rest of Sunday's action.

WTA Tour: Round of 32

No. 23 Maria Sakkari def. Ludmilla Samsonova 6-0, 6-1

No. 29 Jessica Pegula def. No. 6 Karolina Pliskova 6-1, 4-6, 6-4

No. 2 Naomi Osaka def. Nina Stojanovic (walkover)

No. 16 Elise Mertens def. No. 22 Anett Kontaveit 6-2, 0-6, 6-2

Sara Sorribes Tormo def. No. 21 Elena Rybakina 6-1, 3-6, 6-2

Anna Kalinskaya def. No. 12 Garbine Muguruza 4-6, 6-3, 6-4

No. 27 Ons Jabeur def. No. 4 Sofia Kenin 6-4, 4-6, 6-4

No. 8 Bianca Andreescu def. No. 28 Amanda Anisimova 7-6 (4), 6-7 (2), 6-4

Results via WTA.

ATP Tour: Round of 32

No. 18 John Isner def. No. 11 Felix Auger-Aliassime 7-6 (5), 7-6 (5)

No. 7 Roberto Bautista Agut def. No. 31 Jan-Lennard Struff 4-6, 6-3, 6-2

No. 21 Jannik Sinner def. No. 14 Karen Khachanov 4-6, 7-6 (2), 6-4

No. 1 Daniil Medvedev def. Alexei Popyrin 7-6 (3), 6-7 (7), 6-4

Emil Ruusuvuori def. Mikael Ymer 4-6, 6-1, 7-5

No. 32 Alexander Bublik def. James Duckworth 6-4, 6-4

No. 22 Taylor Fritz def. Cameron Norrie 6-4, 3-6, 6-1

Frances Tiafoe def. No. 16 Dusan Lajovic 1-6, 7-5, 6-3

Results via ATP.

Pegula Remains Dominant Over Pliskova

While the rankings heading into the match may have spelled trouble for Pegula, she has starred against Pliskova in the past. Sunday's victory was her third win against Pliskova this season and her fourth overall Top 10 victory.

It looked as though Pegula would take the match in two sets, carrying a dominant 6-1 first-set win into the second set, where she took a 4-1 lead, but Pliskova rallied. The Czech won five games in a row to come back and claim the second set 6-4.

The 2019 Miami Open runner-up was strong again in the final set, forcing a 4-2 lead, but Pegula claimed four straight games for the victory.

Pegula's win sends her to a round-of-16 meeting with No. 23 Maria Sakkari of Greece.

Isner Takes Tiebreaker from Auger-Aliassime (Again)

In 2019, Isner defeated Auger-Aliassime in tiebreakers at the Miami Open semifinal.

When they met again Sunday in the round of 32, he did the same, claiming the 7-6 (5), 7-6 (5) victory, marking four consecutive sets won by Isner in tiebreaker over the Canadian.

The match, which lasted one hour, 49 minutes, had no break points, and Isner won just one more point than his opponent to set up his meeting with Roberto Bautista Agut in the round of 16.

Upsets and Long Matches Mark Afternoon Slate

Italy's Jannik Sinner battled back from a set down to defeat No. 14 Karen Khachanov 4-6, 7-6 (2), 6-4 in a nearly three-hour match.

The win for the 21st-ranked 19-year-old came after unranked Sara Sorribes Tormo upended No. 21 Elena Rybakina in a two-hour, three-set ordeal. The match was her 12th in her last 18 that have lasted for more than two hours.

In evening action, No. 27 Ons Jabeur defeated No. 4 Sofia Kenin to earn her third career win over a player ranked in the top five.