The Australian 11th seed is among a host of former-Grand Slam winners making an appearance on the Cincinnati hardcourts this week, the joint event likely to be the final tune-up for the top players from both the WTA and ATP ahead of the US Open later this month.
All went according to script on day one of action with ninth seeded German Angelique Kerber battling past Italian qualifier Karin Knapp 6-7(6) 6-0 6-1, while 12th seeded Roberta Vinci of Italy also needed three sets to see off American Bethanie Mattek-Sands 6-4 5-7 6-3.
Russian 16th seed Maria Kirilenko was a 4-6 7-6 (4) 7-6 (4) winner over Georgian Anna Tatishvili, while unseeded Venus Williams swept past Slovakia's Jana Cepelova 6-4 6-1 to the approval of the home crowd.
American world number one Serena Williams, fresh off her win in Toronto, headlines a star studded women's field that will feature the top 20 ranked players.
World number three Maria Sharapova, healthy again after a lengthy injury layoff, returns to the court for the first time since Wimbledon against American Sloane Stephens.
Swiss Martina Hingis continued her return to competition teaming up with Slovakian Daniela Hantuchova for a 4-6 6-4 10-5 first round doubles win over Spain's Anabel Medina Garrigues and Italian Flavia Pennetta.
Cincinnati Open results
12-Roberta Vinci (Italy) beat Bethanie Mattek-Sands (U.S.) 6-4 5-7 6-3
Eugenie Bouchard (Canada) beat Monica Puig (Puerto Rico) 6-3 6-4
Venus Williams (U.S.) beat Jana Cepelova (Slovakia) 6-4 6-1
Alisa Kleybanova (Russia) beat Sofia Arvidsson (Sweden) 4-6 6-4 7-6(7)
9-Angelique Kerber (Germany) beat Karin Knapp (Italy) 6-7(6) 6-0 6-1
16-Maria Kirilenko (Russia) beat Anna Tatishvili (Georgia) 4-6 7-6(4) 7-6(4)
Marina Erakovic (New Zealand) beat Carla Suarez Navarro (Spain) 6-3 6-4
Sloane Stephens (U.S.) beat Petra Martic (Croatia) 6-2 3-6 6-3
11-Samantha Stosur (Australia) beat Svetlana Kuznetsova (Russia) 6-1 7-5
Vania King (U.S.) beat Kristina Mladenovic (France) 6-3 6-4
Lauren Davis (U.S.) beat Klara Zakopalova (Czech Republic) 7-6(3) 7-6(1)
Simona Halep (Romania) beat Hsieh Su-Wei (Taiwan) 6-7(5) 6-1 6-2