World number one Serena Williams battled past Christina McHale 6-3, 5-7, 6-2 to advance to the third round of the Miami Open.
Williams, who is still searching for her first title of the year, looked to be in superb form early on as she broke McHale twice en route to taking a 5-1 lead in the first set.
McHale broke back in the seventh game, but Williams went on to clinch the opener without any further problems.
Williams broke immediately in the second set only for McHale to level matters at 5-5 before breaking Williams again in the 12th game to take the second set.
However, Williams returned to her dominant ways in the final set, where she broke McHale twice on her way to winning the match and setting up a third round clash with Zarina Diyas, who beat Daria Gavrilova 7-5, 6-3.
Third seed Agnieszka Radwanska had little trouble progressing to the third round, breaking Alize Cornet’s serve six times in her 6-0, 6-1 rout.
Meanwhile, fifth seed Simona Halep and eighth seed Petra Kvitova are also through to the third round after they beat Daria Kasatkina 6-3, 7-5 and Irina Falconi 6-1, 6-4 respectively.
Yanina Wickmayer provided the biggest upset of the day as she defeated 11th seed Lucie Safarova 6-2, 6-3.