Rome, Italy (SportsNetwork.com) - No. 2 seed Simona Halep, Petra Kvitova and American Venus Williams were second-round winners, while fifth-seeded Caroline Wozniacki was sent packing by fellow former world No. 1 star Victoria Azarenka at the $2.7 million Italian Open.

The 2014 French Open runner-up Halep drilled American Alison Riske 6-3, 6-0 on the red clay at Foro Italico.

The Romanian Halep has already played 32 matches this season, capturing titles in Shenzhen, Dubai and Indian Wells, and perhaps unsurprisingly is battling some minor physical problems.

"I feel good," she said. "I can run, I can play, I can do everything. I will have the chance to win a Grand Slam but it's still very far so I want to try to take match by match and see if that is going to happen."

The fourth-seeded Kvitova rallied from 5-2 down in the third set to beat Italian Karin Knapp 6-3, 4-6, 7-6 (7-1). Kvitova won her 16th WTA title in Madrid last week.

Meanwhile, the unseeded 2013 Rome runner-up Azarenka doused the 2014 U.S. Open runner-up Wozniacki 6-2, 7-6 (7-2) on Day 4.

The Belarusian Azarenka is now 6-4 lifetime against the Danish Wozniacki, including a third-round win in Rome in 2009.

The 14th-seeded former No. 1 Williams grounded recent Marrakech champion Elina Svitolina 6-4, 6-3. Williams was the Rome champ in 1999 and runner-up in 1998.

Sixth-seeded Wimbledon runner-up Genie Bouchard of Canada handled Kazakhstan's Zarina Diyas 6-3, 6-4, while an upset came when Russian qualifier Daria Gavrilova outlasted seventh-seeded former No. 1 and former French Open champ Ana Ivanovic 5-7, 7-6 (7-2), 7-6 (9-7).

Eighth-seeded Russian left-hander Ekaterina Makarova overcame French lucky- loser Kristina Mladenovic 4-6, 6-3, 6-1, while 10th-seeded Spaniard Carla Suarez Navarro blasted Brit Heather Watson 6-1, 6-1.

Jelena Jankovic, the No. 16 seed, beat Magdalena Rybarikova 6-4, 7-6 (7-2). Jankovic was the back-to-back Rome champion in 2007 and 2008 and runner-up in 2010.

More second-round upsets occurred when Romanian Irina-Camelia Begu dismissed ninth-seeded German Angelique Kerber 6-3, 6-3; Romanian qualifier Alexandra Dulgheru came back to erase 12th-seeded Czech Lucie Safarova 1-6, 6-4, 7-6 (8-6); American qualifier Christina McHale stunned 13th-seeded former Roland Garros finalist Sara Errani 6-4, 6-4; and Serbian qualifier Bojana Jovanovski knocked out 15th-seeded American Madison Keys 6-4, 1-6, 6-3. Errani was last year's Italian Open runner-up to three-time winner Serena Williams.

Serena will battle McHale in an all-American affair on Thursday.