Wozniacki felt the wrath of the Roland Garros fans after disputing a line call in her 6-3, 7-6 (8-6) defeat of Aleksandra Wozniak, while Schiavone's 6-1, 6-2 win over Vesna Dolonts unfolded at a half-empty Court Phillipe Chatrier.
Wozniacki, bidding to win a first ever Grand Slam, meets 28th seed Daniela Hantuchova in the last 32, with Schiavone - the first ever Italian woman to win a major - set to face Chinese 29th seed Peng Shuai.
Having won her first set 6-3, Wozniacki found herself 6-3 down in a second-set tie-break when an attempted lob was called long by a line judge, handing Wozniak three set points and a huge chance to level the match.
Wozniacki, the 20-year-old world number one, took exception to the decision and a stand-off with the umpire ensued, prompting jeers to ring out around the Court Philippe Chatrier arena.
The delay appeared to unsettle Canadian qualifier Wozniak, however, and when play resumed she conceded the next five points in succession to hand Wozniacki a place in round three.
"The ball was going very fast, it wasn't slow, and if both the linesman and the umpire didn't see it when it was going like this, I wanted the linesman to confirm it was the mark that was shown," explained Wozniacki.
The centre court was pock-marked by empty seats by the time Schiavone arrived to tackle world number 101 Dolonts in the early evening, despite warm sunshine illuminating proceedings on the western edge of the French capital.
Dolonts, making her main draw debut at Roland Garros, broke Schiavone in her opening game but the tenacious 30-year-old broke straight back and took a 3-1 lead when the Russian found the net with a backhand from the back of the court.
Schiavone promptly sewed up the first set and was quickly on the front foot in the second, breaking Dolonts three times in succession and then overcoming a brief late flurry from her opponent to complete a 72-minute victory.
Russian third seed Vera Zvonareva came within a whisker of succumbing to the biggest upset of the tournament to date before eventually prevailing 4-6, 7-5, 7-5 against injury-stricken German qualifier Sabine Lisicki.
Lisicki, the former world number 22, spurned a match point at 5-2 up in the third set before the injury jinx that kept her off the courts for five months last year returned, prompting a long injury time-out that left her in tears.
Her opponent's momentum having evaporated, Zvonareva proceeded to win the next five games in succession to reach the last 32, after which a weeping Lisicki departed the scene on a stretcher.
Australian eighth seed Samatha Stosur, beaten by Schiavone in last year's final, crushed Romanian 19-year-old Simona Halep 6-0, 6-2 in her second-round match.
The 27-year-old world number six takes on Gisela Dulko in the third round, after the unseeded Argentine comfortably beat Bulgarian 32nd seed Tsvetana Pironkova 6-4, 6-2.
"It's a good match-up for me," said Stosur on the draw with Dulko.
"We know each other's games quite well. It will come down to who can play better on the day."
There were also victories for Serbian former world number one Jelena Jankovic, France's Marion Bartoli and 2009 champion Svetlana Kuznetsova of Russia, the 10th, 11th and 13th seeds respectively.
Bartoli beat Belarusian qualifier Olgo Govortsova 6-4, 6-7 (1-7), 6-2, Jankovic saw off Russia's Vera Dushevina 6-3, 6-2 and Kuznetsova crushed Romanian 20-year-old Irina-Camelia Begu 6-1, 6-1.
- AFPTags: sport, tennis, france First posted May 26, 2011 06:05:00