LONDON, England - It was an especially good day for the Williams sisters in Olympic play at the All-England Club on Monday, as they went a combined 6 for 6 in sets won, including a straight set triumph in their first round doubles match.

After Serena beat Urszula Radwanska and Venus topped Sara Errani in singles, the 2000 and 2008 Olympic doubles gold medalists and reigning Wimbledon champions took on Romanians Sorana Cirstea and Simona Halep. The serve proved the difference, as the Americans lost just four points when getting their first serves in and were not broken while converting on 4 of 6 break point opportunities on their opponents' serve.

The 63 62 triumph upped the Williamses' Olympic record to 11-0 and their grass court record to 39-2. The competition gets tougher on Tuesday, as they square off with fifth-seeded Germans Angelique Kerber and Sabine Lisicki.

"It feels like we just got out of Wimbledon, and we are back at it again," Serena Williams said. "So it felt really good."

Serena even left the door open to playing a third event this week, as the deadline to sign up for mixed doubles is Tuesday. "We'll see at 11am tomorrow," she said. "I'll keep you guys on your toes."

Other first round winners included No.4 seeds Andrea Hlavackova and Lucie Hradecka, the Radwanskas and Andreja Klepac and Katarina Srebotnik.

Czechs Hlavackova and Hradecka got past Hungarians Timea Babos and Agnes Szavay, 61 67(5) 62. Poles Agnieszka and Urszula Radwanska shook off first and second round losses in singles, respectively, and recorded a 62 61 rout of Slovakians Dominika Cibulkova and Daniela Hantuchova to set up a clash on Tuesday against top-seeded Americans Liezel Huber and Lisa Raymond. Slovenians Klepac and Srebotnik lost three straight games from 3-3 in the second set but jumped out to a 4-1 third set lead en route to edging Georgians Margalita Chakhnashvili and Anna Tatishvili, 76(0) 36 62. Next up for them are second-seeded Italians Sara Errani and Roberta Vinci.

One quarterfinal match-up was set, with third-seeded Maria Kirilenko and Nadia Petrova and Peng Shuai and Zheng Jie winning their second round matches. The Russians beat Kazaks Yaroslava Shvedova and Galina Voskoboeva, 63 62. The Chinese handled eighth-seeded Nuria Llagostera Vives and María José Martínez Sánchez, 64 62, converting on 79 percent of their second serve points compared to just 42 percent for the Spaniards. Llagostera Vives and Martínez Sánchez were the Olympics' first seeds to fall.