NEW YORK: French qualifier Julie Coin, ranked 188th in the world, pulled off a massive upset by ousting world No. 1 Ana Ivanovic in second-round action at the 2008 U.S. Open.

Additionally, Serena and Venus Williams, and Olympic silver medalist Dinara Safina all advanced in straight sets on Day 4.

But the spotlight shone on the 25-year-old Coin, who posted one of the biggest upsets in U.S. Open history by erasing Ivanovic in 6-3, 4-6, 6-3 fashion at Arthur Ashe Stadium.

Fourth-seeded Serena, a two-time U.S. Open champ and eight-time major titlist, needed just 58 minutes to notch a 6-1, 6-1 win over Russian Elena Vesnina.

The seventh-seeded and two-time champion Venus waltzed past 32-year-old Rossana De Los Rios of Paraguay 6-0, 6-3 on Day 4 at the USTA Billie Jean King National Tennis Center..

Venus moved on in one hour after converting on a fifth match point and will face 27th-seeded Ukrainian Alona Bondarenko in a third-rounder this weekend. Bondarenko blitzed German Sabine Lisicki 6-4, 1-6, 6-4 to advance.

A sixth-seeded Safina blew past Italian Roberta Vinci 6-4, 6-3. The Russian star is the hottest player in women's tennis, having reached the final in six of her last seven tournaments and winning three titles. She was the French Open runner-up to Ivanovic back in June and the runner-up to fellow Russian Elena Dementieva at the Beijing Games earlier this month.

Up next for the surging Safina will be Swiss Timea Bacsinszky, who moved on by dousing Taipei's Yung-Jan Chan 6-3, 6-2.

Another top-10 victor was Poland's Agnieszka Radwanska, as the No. 9 seed got past Colombian Mariana Duque Marino 6-0, 7-6 (7-3). Radwanska will face fellow rising star Dominika Cibulkova in the third round.

Sixteenth-seeded Italian Flavia Pennetta snuck past Chinese Shuai Peng 6-2, 6-7 (8-10), 6-1, while an upset came when Italian Tathiana Garbin grounded 13th-seeded Hungarian Agnes Szavay 5-7, 6-2, 6-3. Szavay was a quarterfinalist here a year ago.

Seventeenth-seeded Frenchwoman Alize Cornet topped American Bethanie Mattek 7-6 (7-5), 6-1, while an 18th-seeded Cibulkova drubbed Romanian Ioana Raluca Olaru 6-2, 6-2 and 19th-seeded Russian Nadia Petrova pasted Taipei's Su-Wei Hsieh 6-4, 6-2.

A mild upset came when France's Severine Bremond bounced 20th-seeded Czech Nicole Vaidisova 7-5, 6-3, while Sugiyama came from behind to beat Belarusian Olga Govortsova 4-6, 7-6 (7-4), 6-1.

The former world No. 1 Mauresmo snuck into the third round by overcoming Estonian Kaia Kanepi 2-6, 6-4, 6-0. The oft-injured 32nd-seeded Mauresmo is a two-time major titlist.

In other second-round play, German Anna-Lena Groenefeld grounded Aussie Jessica Moore 6-1, 6-3.