London - Five-time champion Venus Williams suffered her worst Wimbledon defeat in 15 years on Monday, slumping to a first round exit at the hands of Russia's Elena Vesnina, but defiantly insisted she will not quit.
Williams lost 6-1, 6-3 to the 79th-ranked Russian in what was the 32-year-old's first opening round loss at the All England Club since her 1997 debut.
But the former world number one - the champion in 2000, 2001, 2005, 2007 and 2008 - believes she can still compete at the top level despite her ranking having slipped to 58 after a six-month absence fighting serious illness.
"There's no way I will give up just because I have had a hard time in the first four or five friggin' tournaments back. That's not me," said a feisty Williams at a post-match news conference.
When asked if she will play at Wimbledon in 2013, she was adamant.
"Sure," she said. "I feel like I am a great player who has had to deal with exceptional circumstances.
"I don't have time to feel negative. It doesn't feel good. I am as tough as nails, I don't have time to be sorry for myself.
"I can keep going for a while. You will see me playing here again next year."
The American star arrived at Wimbledon, where she was unseeded for the first time since her 1997 debut, short of confidence having been sidelined with Sjogern's Syndrome, a disease which causes joint pain and fatigue.
Monday's defeat was just her fourth loss at the first round stage of a Grand Slam against 52 wins.
After pulling out of the 2011 US Open, she only returned at Miami in March when her ranking was 134.
That presented her with an immediate problem - her ranking was too low to gain a place at the Olympics.
"I am proud of the efforts I made to get my ranking back up in time for the Olympics," she said.
"That was one of the toughest things I have ever done in my life. I came back early, but I can't say if I am paying for that now."
Since her return, Williams has reached three quarter-finals - Miami, Charleston and Rome.
But she was a second round loser at the French Open where the impact of her efforts began to tell.
"I have lost before and I know how to deal with it," said Williams after Monday's 75-minute defeat out on Court Two.
"I came in with a positive attitude and wanted to do my best. Life is challenging but I am up for a challenge."
Vesnina, who had lost in the first round of nine of her last 10 Grand Slam appearances, will face Polish third seed Agnieszka Radwanska for a place in the last 32.
Results on the first day of Wimbledon at the All England Club on Monday (x denotes seeding):
Novak Djokovic (SRB x1) bt Juan Carlos Ferrero (ESP) 6-3, 6-3, 6-1
Ryan Harrison (USA) bt Lu Yen-Hsun (TPE) 4-6, 6-3, 6-4, 6-2
Benjamin Becker (GER) bt James Blake (USA) 6-7 (4/7), 7-5, 6-0, 6-4
Radek Stepanek (CZE x28) bt Sergiy Stakhovsky (UKR) 6-1, 1-0 - retired
Viktor Troicki (SRB) bt Marcel Granollers (ESP x24) 7-5, 7-6 (7/5), 3-6, 2-6, 8-6
Martin Klizan (SVK) bt Juan Ignacio Chela (ARG) 7-5, 3-6, 7-6 (8/6), 1-6, 11-9
Jrmy Chardy (FRA) bt Filippo Volandri (ITA) 6-0, 6-1, 1-0 - retired
Juan Monaco (ARG x15) bt Leonardo Mayer (ARG) 6-4, 7-6 (7/5), 7-6 (7/5)
Ruben Bemelmans (BEL) bt Carlos Berlocq (ARG) 7-5, 6-7 (4/7), 6-3, 7-6 (7/2)
Richard Gasquet (FRA x18) bt Tobias Kamke (GER) 6-2, 6-2, 6-2
Florian Mayer (GER x31) bt Dmitry Tursunov (RUS) 7-6 (7/3), 6-2, 6-3
Philipp Petzschner (GER) bt Blaz Kavcic (SLO) 6-4, 6-4, 6-2
Jerzy Janowicz (POL) bt Simone Bolelli (ITA) 3-6, 6-3, 6-3, 6-3
Ernests Gulbis (LAT) bt Tomas Berdych (CZE x6) 7-6 (7/5), 7-6 (7/4), 7-6 (7/4)
Roger Federer (SWI x3) bt Albert Ramos (ESP) 6-1, 6-1, 6-1
Fabio Fognini (ITA) bt Michael Llodra (FRA) 3-6, 6-3, 6-4, 7-5
Michael Russell (USA) bt Adrin Menndez (ESP) 6-3, 6-1, 7-6 (9/7)
Julien Benneteau (FRA x29) bt Gilles Muller (LUX) 6-2, 7-5, 7-6 (7/4)
Fernando Verdasco (ESP x17) bt Yeu-Tzuoo Wang (TPE) 7-6 (7/3), 6-4, 7-5
Grega Zemlja (SLO) bt Joshua Goodall (GBR) 6-4, 3-6, 7-6 (7/3), 6-4
Xavier Malisse (BEL) bt Marinko Matosevic (AUS) 6-2, 6-2, 7-5
Gilles Simon (FRA x13) bt Paul-Henri Mathieu (FRA) 6-3, 5-4 - retired
Alejandro Falla (COL) bt John Isner (USA x11) 6-4, 6-7 (7/9), 3-6, 7-6 (9/7), 7-5
Igor Andreev (RUS) bt Oliver Golding (GBR) 1-6, 7-6 (7/4), 7-6 (9/7), 7-5
Denis Istomin (UZB) bt Andreas Seppi (ITA x23) 6-7 (2/7), 6-4, 3-6, 6-3, 8-6
Mikhail Youzhny (RUS x26) bt Donald Young (USA) 4-6, 6-3, 6-2, 6-3
Inigo Cervantes-Huegun (ESP) bt Flavio Cipolla (ITA) 2-6, 6-7 (4/7), 6-3, 6-2, 6-1
Ryan Sweeting (USA) bt Potito Starace (ITA) 6-2, 2-0 - retired
Janko Tipsarevic (SRB x8) bt David Nalbandian (ARG) 6-4, 7-6 (7/4), 6-2
Maria Sharapova (RUS x1) bt Anastasia Rodionova (AUS) 6-2, 6-3
Tsvetana Pironkova (BUL) bt Vesna Manasieva (SRB) 5-7, 6-0, 7-5
Su-Wei Hsieh (TPE) bt Virginie Razzano (FRA) 6-2, 6-4
Stphanie Foretz (FRA) bt Monica Niculescu (ROM x29) 6-4, 3-6, 6-3
Petra Cetkovsk (CZE x23) bt Vania King (USA) 6-4, 6-2
Sloane Stephens (USA) bt Karolna Plskov (CZE) 6-2, 6-2
Bojana Jovanovski (SRB) bt Eleni Daniilidou (GRE) 5-7, 6-3, 2-0 - retired
Sabine Lisicki (GER x15) bt Petra Martic (CRO) 6-4, 6-2
Silvia Soler (ESP) bt Edina Gallovits (ROM) 4-6, 6-4, 10-8
Andrea Hlavckov (CZE) bt Kai-Chen Chang (TPE) 6-1, 6-2
Kim Clijsters (BEL) bt Jelena Jankovic (SRB x18) 6-2, 6-4
Mathilde Johansson (FRA) bt Lesya Tsurenko (UKR) 3-6, 6-0, 6-3
Ekaterina Makarova (RUS) bt Alberta Brianti (ITA) 6-2, 3-6, 6-3
Angelique Kerber (GER x8) bt Lucie Hradeck (CZE) 6-4, 6-1
Agnieszka Radwanska (POL x3) bt Magdalna Rybrikov (SVK) 6-3, 6-3
Elena Vesnina (RUS) bt Venus Williams (USA) 6-1, 6-3
Heather Watson (GBR) bt Iveta Benesova (CZE) 6-2, 6-1
Jamie Hampton (USA) bt Daniela Hantuchova (SVK x27) 6-4, 7-6 (7/1)
Nadia Petrova (RUS x20) bt Maria Elena Camerin (ITA) 6-0, 6-2
Tmea Babos (HUN) bt Melanie Oudin (USA) 6-4, 4-6, 6-3
Anna Tatishvili (GEO) bt Tamarine Tanasugarn (THA) 6-4, 6-2
Camila Giorgi (ITA) bt Flavia Pennetta (ITA x16) 6-4, 6-3
Li Na (CHN x11) bt Ksenia Pervak (KAZ) 6-3, 6-1
Sorana Cirstea (ROM) bt Pauline Parmentier (FRA) 6-4, 6-1
Lourdes Domnguez (ESP) bt Naomi Broady (GBR) 6-4, 7-6 (7/4)
Maria Kirilenko (RUS x17) bt Alexandra Cadantu (ROM) 6-3, 6-1
Peng Shuai (CHN x30) bt Sandra Zaniewska (POL) 6-2, 6-7 (3/7), 6-3
Ayumi Morita (JPN) bt Jarmila Gadjosova (AUS) 6-4, 6-3
Arantxa Rus (NED) bt Misaki Doi (JPN) 7-5, 6-3
Samantha Stosur (AUS x5) bt Carla Surez (ESP) 6-1, 6-3