Updated

Second-seeded former champion Maria Sharapova and fourth-seeded Agnieszka Radwanska cruised in their third-round matches Friday at the Australian Open.

Sharapova, the 2008 champion and two-time Aussie Open runner-up, rolled over 25th-seeded fellow former world No. 1 Venus Williams, 6-1, 6-3. Sharapova failed to lose a game in her first two matches, while Williams had dropped only seven games over her first two rounds. Sharapova still managed to set a new Open Era Grand Slam record by winning 28 straight games to start the tournament.

Despite only winning 5-of-13 break points, Sharapova was aided by 26 unforced errors by the seven-time Grand Slam champion Williams, who lost to her younger sister Serena in the 2003 Aussie Open finale.

"I think when we both looked at the draw, it was a matchup we were both looking forward to," Sharapova said. "She's a tremendous athlete and a great champion."

Sharapova is now 5-3 lifetime against Venus, who had won their previous two Grand Slam meetings.

The reigning French Open titlist and career Grand Slam winner Sharapova, who lost to Victoria Azarenka in last year's Aussie finale, advanced to face Belgian Kirsten Flipkens, who needed three sets to get past Russian Valeria Savinykh 6-2, 4-6, 6-3 at Melbourne Park.

Meanwhile, the 2012 Wimbledon runner-up Radwanska whipped Great Britain's Heather Watson 6-3, 6-1 for her 12th straight victory following back-to- back season-opening titles in Auckland and Sydney.

"I'm extremely happy to be playing my best tennis from the beginning of the year," Radwanska said.

The 23-year-old from Poland will face 13th-seeded Ana Ivanovic in the fourth round.

The former French Open champion Ivanovic, the 2008 Aussie Open runner-up to Sharapova, got past fellow Serb and fellow former No. 1 Jelena Jankovic, handling the 22nd seed 7-5, 6-3 on Day 5 of the fortnight.

Fifth-seeded Angelique Kerber, who turned 25 on Friday, was also a straight- set winner, defeating American teenager Madison Keys 6-2, 7-5 at Rod Laver Arena, while sixth-seeded Li Na earned a 6-4, 6-1 victory over 27th-seeded Sorana Cirstea of Romania. Li was the French Open champion and Aussie Open runner-up two years ago.

Up next for Kerber will be Russian Ekaterina Makarova, while Li will face German Julia Goerges.

Also on Friday, 11th-seeded French slugger Marion Bartoli was ousted by the 19th-seeded Makarova 6-7 (4-7), 6-3, 6-4 in a match that lasted nearly three hours, while the 18th-seeded Goerges overcame 56 unforced errors to outlast China's Zheng Jie 6-3, 1-6, 7-5.

The third round will conclude on Saturday, highlighted by matches for the reigning world No. 1 and reigning Melbourne titlist Azarenka and the third-seeded former No. 1 and five-time Aussie champ Serena. Azarenka will take on American Jamie Hampton, while the American great Serena will be opposed by Japan's Ayumi Morita.

Azarenka beat Sharapova in last year's Aussie final and lost to Serena in the U.S. Open title tilt. The 15-time Grand Slam champion Serena is the reigning Wimbledon and U.S. Open champ who is seeking a third straight major title.

In some other third-round action on Saturday, 10th-seeded former world No. 1 and former U.S. Open runner-up Caroline Wozniacki will face Ukrainian Lesia Tsurenko, 29th-seeded rising American Sloane Stephens will battle talented British left-hander Laura Robson, and two-time major champion Svetlana Kuznetsova will tangle with Spaniard Carla Suarez Navarro.