Watson beat Italian Alberta Brianti in the final qualifying round
Britain's Heather Watson beat Noppawan Lertcheewakarn of Thailand 6-1 6-1 to make the Auckland Classic second round.
The 18-year-old's opponent had defeated GB compatriot Katie O'Brien in qualifying, but there were no such problems for the world number 176.
Watson faces Carla Suarez Navarro, the Spaniard ranked 57, in round two.
Meanwhile the defending champion, Belgian Yanina Wickmayer, beat Russian former number one Dinara Safina 6-3 6-7 (2-7) 6-1 in a hard-fought encounter.
The Belgian, ranked 23, came out on top after a series of baseline battles with Safina, who fought a back injury in 2010.
Wickmayer, who is seeded second behind Maria Sharapova, will take on German qualifier Sabine Lisicki in the second round on Wednesday.
Guernsey-born Watson, who won the US Open junior title in 2009, is enjoying a fine run of form.
She moved into the world top 200 for the first time in November 2010 after winning the Tevlin Challenger, an ITF tournament in Canada, and did not face a single break point against Lertcheewakarn.
Suarez Navarro is likely to provide stern opposition. She is seeded eighth and saw off Romina Oprandi of Italy 6-3 7-6 in the first round.
Watson's fellow Briton Anne Keothavong is already through to the second round and will play Ukrainian Kateryna Bondarenko.
Among Tuesday's other matches, Lisicki beat Argentine Florencia Molinero 6-1, 6-3 while sixth seed Elena Vesnina of Russia defeated Kiwi wildcard Marina Erakovich 6-2 6-2.