The seven-time grand slam singles champion has not won a tournament since victory in Luxembourg in October 2012, but she has stated her aim of reaching the final in New Zealand.
The 33-year-old is now world number 47, although much of her tumble down the rankings can be attributed to the Sjogren's syndrome she was diagnosed with in 2012.
On Monday the American was far more effective than her opponent in the first set which she won 6-3.
However, the second proved to be a different proposition with Williams producing five double faults as it went to a tie-break.
Ultimately she edged through thanks to a powerful first serve, winning the tie-break comprehensively for a straight-sets victory.
Fifth seed Jamie Hampton overcame a dreadful first set to ultimately ease through against Tamira Paszek 1-6 6-0 6-3.
The Austrian had an almost unplayable serve in the first set, but that went from sublime to ridiculous in the second when she won no points on her first serve.
Although she improved in the decider, the 151 rankings gap was ultimately reflected in the victory which lasted one hour 33 minutes.
Seventh seed Mona Bartel will not take any further part in New Zealand, though, as she produced seven double faults en route to a 6-4 6-3 defeat by Austrian Yvonne Meusberger.
Kurumi Nara beat Alexandra Cadantu who retired when 4-0 down in the second set, the Japanese winning 6-1 4-0.
Johanna Larsson beat Lourdes Dominguez Lino 7-5 6-0, Karolina Pliskova defeated Paula Ormaechea 7-6 (7/2) 6-1, while Garbine Muguruza downed Christina McHale 6-4 6-3.