Serena Williams made it 750 career wins as she progressed past a spirited Zarina Diyas in the third round to stay on track for a fourth consecutive Miami Open title.
Williams had to grind through a tough match on the way to securing a 7-5 6-3 victory.
Neither player could find their rhythm on serve in an error-strewn first set in which Williams served three double faults to Diyas' two.
Diyas even broke Williams twice, but the world number one bettered that by breaking the 22-year-old three times on the way to claiming the first set.
It looked to be much more straightforward in the second as Williams powered to a 4-0 lead, finding her touch on serve and bullying Dimas on return with her trademark power, but the youngster fought back admirably to 4-3 before the American saw out the match.
Williams hit 27 winners, but also struck 37 unforced errors during the tough contest.
"She started with a new strategy, but I eventually figured it out," Williams said.
"She played well. I saw she's ranked 97 in the world and I thought, 'she's doing great,' she has such a bright future."
Williams will now take on Svetlana Kuznetsova in the fourth round after she saw off Carolina Garcia.