Former world No.1 Venus Williams has come from behind to beat Austrian Yvonne Meusburger in three sets and move into the ASB Classic tennis quarter-finals.
The American won 4-6 6-3 6-2 to set up a meeting with unseeded Spaniard Garbine Muguruza.
Williams brought her power and athleticism to the contest, and also produced plenty of unforced errors.
A large proportion of those came in the opening set, when she twice dropped serve, the first time after the players returned to court following a 20-minute rain interruption.
Williams was able to break Meusburger to love in the next game to level at 2-2, but then lost her serve again immediately.
Meusburger, who at No.49 is ranked two places below Williams, produced some solid tennis to hold on to her advantage and secure the first set.
Williams claimed the only break of the second set but still had her struggles before squaring the match.
Serving at 5-3, she came up with two double faults before bouncing back from 0-40 down.
She maintained her momentum into the final set, eventually closing out the match with relative ease.
Earlier on Wednesday, Belgium's Kirsten Flipkens and American Jamie Hampton halted the cull of the seeds by making safe passage through to the last eight.
The respective tournament No.3 and No.5 were among just three seeds to progress past the opening round in Auckland.
In the second round, Flipkens downed Czech opponent Karolina Pliskova 6-4 6-3.
Hampton, a semi-finalist last summer, beat Pliskova's twin sister, qualifier Kristyna, 6-3 6-4.
The other remaining seed, second-seeded Serbian Ana Ivanovic, is in action in the night session against Sweden's Johanna Larsson.
