Serena Williams eased into the third round of the Australian Open with a 6-1, 6-2 win over Vesna Dolonc.
By extending her winning stretch to 24 matches dating back to August, and improving her career mark to 60-8 at Melbourne Park, she also equalled Margaret Court's record 60 match wins at the Australian Open in the Open era.
Novak Djokovic also marched into the third round with a 6-0, 6-4, 6-4 win over Leonardo Mayer.
Second-seeded Djokovic, aiming to be the first man in the Open era to win four consecutive Australian Open titles, did not face a break point.
Williams next meets Daniela Hantuchova, who was on court for three hours, 13 minutes in her 6-3, 3-6, 12-10 win over Karolina Pliskova.
Li Na through
Earlier, Li Na opened proceedings when she completed back-to-back wins over the two youngest players in the draw.
The 2011 French Open champion, a two-time finalist at Melbourne Park, conceded just 10 points in the first set en route a 6-0, 7-6 win over 16-year-old Belinda Bencic.
Angelique Kerber advanced to a match against American Alison Riske, who trounced Yanina Wickmayer 6-1, 6-1.
Australian wild-card entry Casey Dellacqua upset Kirsten Flipkens 6-3, 6-0.
The tournament's heat rule went into effect in the first match on Margaret Court Arena, giving Sabine Lisicki and Monica Niculescu a 10-minute break after the second set.
Niculescu returned to win 2-6, 6-2, 6-2 and will next play Ekaterina Makarova, who followed up her first-round win over Venus Williams with a 6-2, 7-5 victory over American Irina Falconi.
On the men's side, David Ferrer beat Adrian Mannarino of France 7-6, 5-7, 6-0, 6-3 to progress along with Tomas Berdych and Richard Gasquet, Tommy Robredo, Jerzy Janowicz and Jeremy Chardy.
Men's second round results (selected):
Novak Djokovic (2) def. Leonardo Mayer 6-0, 6-4, 6-4
David Ferrer (3) def. Adrian Mannarino 7-6, 5-7, 6-0, 6-3
Tomas Berdych (7) def. Kenny De Schepper 6-4, 6-1, 6-3
Richard Gasquet (9) def. Nikolay Davydenko 7-6, 6-4, 6-4
Florian Mayer def. Mikhail Youzhny (14) 6-4, 3-6, 6-3, 3-6, 6-3
Women's second round results (selected):
Serena Williams (1) def. Vesna Dolonc 6-1, 6-2
Li Na (4) def. Belinda Bencic 6-0, 7-6
Angelique Kerber (9) def. Alla Kudryavtseva 6-4, 6-2
Ana Ivanovic (14) def. Annika Beck 6-1, 6-2
Monica Niculescu def. Sabine Lisicki (15) 2-6, 6-2, 6-2
Samantha Stosur (17) def. Tsvetana Pironkova 6-2, 6-0