Former world No. 1 star Venus Williams was an easy opening-round winner Tuesday at the inaugural WTA Brasil Tennis Cup.

After having her first-round match rained out here on Monday, the top-seeded American Williams promptly dismissed Croat Mirjana Lucic-Baroni 6-3, 6-3 in 79 minutes on the hardcourts at Federacao Catarinense de Tenis, where rain interrupted play once again on Tuesday.

An upset occurred when Russian Olga Puchkova overcame third-seeded Belgian Kirsten Flipkens, 2-6, 6-4, 6-4.

Also, Slovak Jana Cepelova upended eighth-seeded German Annika Beck in the lone second-round match of the day. Cepelova prevailed in a tight first-set tiebreaker before ultimately claiming a 7-6 (8-6), 6-4 decision.

Meanwhile, fifth-seeded Slovak Magdalena Rybarikova erased 42-year-old Japanese Kimiko Date-Krumm 6-3, 6-0 and seventh-seeded Frenchwoman Kristina Mladenovic handled Britain's Anne Keothavong 6-3, 6-4.

Additional wins came for German Tatjana Malek, Brazilian wild card Beatriz Haddad Maia, Hungarian Timea Babos, and Spaniard Garbine Muguruza, who is rewarded with a second-round bout against the seven-time Grand Slam singles champion Williams on Wednesday.