The manner of her defeat inevitably led to speculation that the 37-year-old may have had a physical problem that stopped her from competing with the effectiveness she had shown in earlier rounds.
Venus Williams moved within two wins of a possible sisterly showdown with Serena in the semi-finals of the US Open by beating German 26th seed Laura Siegemund to reach the fourth round on Saturday.
World No 1 Serena Williams and her sister Venus tried their hand at cricket with the Melbourne Renegades players on a hotel roof top on Thursday.
Serena Williams applied some coaching tips from older sister Venus in her 6-3 6-2 thumping of sixth-seeded Dinara Safina on Friday that put the American into the finals of the US Open.
A display of raw desire over a decade ago from sister Serena inspired Venus Williams to ascend the summit of the women's game but there will be no room for sentiment when the siblings meet for the fourth time in a Wimbledon final on Saturday.
Top seed Venus Williams was stunned in the first round of the Memphis International by Czech qualifier Petra Kvitova.
Flavia Pennetta stunned Venus Williams with an impressive 6-4, 7-6 win to reach the Bangkok Open final.
Madison Keys continued to ride her wave of success, fuelled in part by celebratory chocolate biscuits, as she advanced to her first Grand Slam semi-final with a gutsy 6-3, 4-6, 6-4 victory over Venus Williams on Wednesday.
Unseeded Sloane Stephens got the better of fellow-American Venus Williams in a thrilling contest to make it to her first Grand Slam final, at the US Open, in New York, on Thursday.
The American was one game away from tumbling out but, as rain began to fall again on the grasscourt tournament, she outsmarted Akiko Morigami 6-2 3-6 7-5.
Serena Williams capped off yet another successful day at Wimbledon for America's premier tennis family as she followed up her singles triumph by winning the doubles title with sister Venus on Saturday.
Venus Williams suffered a shock 4-6, 7-6, 6-4 defeat by France's Virginie Razzano in the Japan Open final.
Nadia Petrova lost 6-3, 6-3 to Italy's Mara Santangelo in the second round of the Warsaw Cup.
Wimbledon champion Venus Williams blasted past Alona Bondarenko of Ukraine 6-1 6-2 on Friday to charge into the fourth round of the U.S. Open.
Venus Williams gave a supreme effort in the Fed Cup semi-final against Russia after coming off the high of winning her fourth Wimbledon title but came up short in Sunday's decisive doubles match in Stowe, Vermont.
The 27-year-old American beat France's Marion Bartoli 6-4, 6-1 in the final.
Fourth-seeded Venus Williams outpowered Bulgarian Tatiana Poutchek 6-1 6-2 to move into the second round of the Istanbul Cup on Tuesday.
Venus Williams beat top seed Angelique Kerber on Wednesday to advance to a Miami Open semi-final against Britain's Johanna Konta.
Top seed Maria Sharapova dodged the showers on her way to a 6-3, 6-2 victory over Taiwan's Chan Yung-Jan to set up a third round encounter against Venus Williams at the Sony Ericsson Open on Saturday.
The American has targeted a return to the world's top 16 by the French Open.
Ekaterina Makarova, who upset an injured Serena Williams in the fourth round of the 2012 Australian Open, completed a Melbourne Park sweep of the Williams sisters by eliminating Venus 2-6, 6-4, 6-4 to advance to the second round on Monday.
Injured Venus Williams will join her sister Serena on the Fed Cup sidelines with Vania King named to take her place on the US team that will play the quarter-finals in Antwerp against Belgium.
British World No. 3 Andy Murray cruised to a straightforward victory over Bernard Tomic at the Sony Open but the Williams sisters had contrasting fortunes in Miami on Saturday.
A rare astronomical phenomenon on June 8, known as 'Transit of Venus', will turn the planet into a 'pinhead-sized black dot'.
Wimbledon champion Venus Williams will get back into serious action on Saturday when she plays the second singles rubber against Nadia Petrova, in the Fed Cup semi-final.
Defending champion Andy Murray's match will complete a heavyweight Centre Court lineup on Friday that boasts four former Wimbledon winners and includes Venus Williams' return to the main stage.
Serena Williams was left all alone trying to crush an unlikely uprising on Wimbledon's hallowed lawns on Tuesday as sister Venus and Kim Clijsters suffered shock defeats in the women's quarter-finals.
Top seed Caroline Wozniacki and former World No 1 Venus Williams ensured Auckland Classic organisers' dream final remained on track with the duo both recording comfortable victories in their first round matches on Tuesday.
Champion Venus Williams was knocked out of the Family Circle Cup beaten 7-5, 6-4 by 17-year-old Tatiana Golovin of France.
IMAGES from the PNB Paribas Open played at Indian Wells in California on Monday
Venus Williams' record-equalling fifth Olympic tennis medal was silver rather than gold as she and partner Rajeev Ram lost an all-American mixed doubles final to Bethanie Mattek-Sands and Jack Sock on Sunday .
Belgian Kim Clijsters brought a swift end to Venus Williams's 15-match winning streak with a 6-2, 6-1 win in the Sony Ericsson Open final on Saturday. The 14th seed needed only 58 minutes to defeat the third-seeded American, who played with bandaging on both legs and said afterwards she may have trained too hard during the tournament.
The world number two said her near-misses initially left her deflated and sick of tennis, but she was now over the pain.
Venus Williams and Vera Zvonareva registered second-round victories at the Advanta Championships in Philadelphia on Thursday.
Venus Williams staged a spirited comeback to down third seed Petra Kvitova 4-6, 7-5, 6-4 and reach the third round of the BNP Paribas Open in Indian Wells on Saturday.
Venus Williams crushed Frenchwoman Alize Cornet 6-3, 6-0 in the final of the Dubai Championship on Saturday, the veteran American bagging her first singles title since 2012.
"I generally don't play with pain, but this is a Grand Slam and I just wanted to win," said the American.\n\n
Venus Williams bravely fought off five match points to stun third seed Patty Schnyder 2-6, 7-6, 6-2 to enter the final in Stanford
The 29-year-old American romped to a 5-0 lead against Poland's Agnieszka Radwanska and completed a 6-1 6-2 victory on auto-pilot as slumbering Court One fans applauded politely in temperatures soaring into the 30s Celsius again.