Second seed Naomi Osaka picked up where she left off at last month's Australian Open, winning her first match since lifting the title in Melbourne.
Osaka earned her place in the Miami Open third round on Friday with a hard-fought straight-sets victory over Australian Ajla Tomljanovic.
Australian Open runner-up Jennifer Brady was knocked out in the second round by 58th-ranked Sara Sorribes Tormo.
Brady's defeat was the major surprise on Friday, with Sorribes Tormo fighting back from a set down to win.
Top 10 seeds Karolina Pliskova, Bianca Andreescu and Sofia Kenin also progressed, with the latter coming from a set behind to beat Andrea Petkovic.
OSAKA CONTINUES WINNING RUN
Osaka extended her winning streak to 22 matches, although it was not easy against Tomljanovic.
The Japanese got the edge 7-6 (7-3) 6-4, firing down 36 winners, including 13 aces in a match lasting one hour, 38 minutes.
"This is my first match since Australia, so I just really wanted to play well," Osaka said in her on-court post-match interview. "I kind of feel like I'm at home here, because I grew up [near here] for most of my life."
Tomljanovic did not go down without a fight but was let down by 24 unforced errors.
Osaka will next face Serbian qualifier Nina Stojanovic in the third round.
BRADY BEATEN AGAIN
World number 14 Brady succumbed to in-form Monterrey Open semi-finalist Sorribes Tormo 3-6 6-4 6-1.
Brady had a dream run to the final at the Australian Open last month but came back to earth with a thud against the Spaniard, who has won 10 of her past 11 matches.
The match lasted two hours, 22 minutes, with Sorribes Tormo finding the edge in the last as Brady's first-serve percentage dropped to 30.8 per cent.
Brady's defeat comes a few weeks after being humbled by Anett Kontaveit in less than an hour in the Qatar Open first round.
MIXED BAG FOR SEEDS
Tenth seed Kiki Bertens, in her third match back from Achilles surgery, was knocked out by Russian qualifier Ludmilla Samsonova 6-2 6-1 inside an hour.
Fourth seed and last year's Australian Open champion Kenin responded after losing the first set to defeat Andrea Petkovic, winning 6-7 (6-8) 6-1 6-3. The match was Kenin's first since appendix surgery.
Sixth seed Pliskova comfortably got past Zheng Saisai 6-2 6-1 and 2019 US Open champion Andreescu triumphed over Tereza Martincova 7-6 (7-5) 6-2.
Seeds Elena Rybakina, Kontaveit, Maria Sakkari, Ons Jabeur and Amanda Anisimova all won, with 20th seed Petra Martic and Sloane Stephens both knocked out.