Wang won 81 per cent of her first-serve points and saved four of the five break points she faced. She failed to take advantage of three set points on Bronzetti's serve at 5-4 in the first set, then needed two more set points to wrap up the tiebreaker. The lone break in the second set gave Wang a 3-2 lead.
In other opening-round action, fifth-seeded Diane Parry won an all-French matchup against Jessika Ponchet 6-3, 7-6, eighth-seeded Yue Yuan of China rallied past Australia's Arina Rodionova 3-6, 6-3, 6-1 and Colombia's Camila Osorio routed France's Alize Cornet 6-3, 6-2.
San Diego Open
Canada's Marina Stakusic beat Russia's Marina Melnikova 6-4, 5-7, 6-1 in a first-round matchup of qualifiers at San Diego. Stakusic, 19, is ranked 283rd in the world; Melnikova, 35, is ranked 440th.
Stakusic had a 4-0 edge in aces and she won 78 per cent of Melnikova's second-serve points. Her second-round foe will be either seventh-seeded Croatian Donna Vekic or Katherine Hui, a 19-year-old wildcard entrant who is a San Diego native.
Other first-round winners included China's Xinyu Wang, Australia's Daria Saville, Great Britain's Katie Boulter and Germany's Jule Niemeier. Sixth-seeded Marta Kostyuk of Ukraine outlasted US qualifier Ann Li 6-4, 4-6, 6-2 in the last match of the night.