MIAMI, March 29: World number one Roger Federer's 12-match winning streak ended when he went down 6-3 6-3 to 17-year-old Spaniard Rafael Nadal in the third round of the Nasdaq-100 Open on Sunday.

Before he ran into Nadal, the Swiss player had won 28 of his last 29 matches stretching back to the Masters Cup last November, including his Australian Open victory and back-to-back titles in Dubai and Indian Wells.

Former world number ones Lleyton Hewitt and Jennifer Capriati were also shown the exit door on a day of upsets. Hewitt suffered a 6-4 7-5 defeat by Romania's Andrei Pavel while women's fourth seed Capriati was stunned 6-2 6-4 by Greece's Eleni Daniilidou.

Nadal and Tim Henman (who defeated Federer in Rotterdam in February) are the only men to have beaten the world number one in four months. The Spanish teenager showed no fear, breaking serve early in the first set and hitting with relentless aggression until Federer's serve cracked again at 2-3 in the second. Nadal, seeded 32, then served the match out with an assurance which belied his years.

Second seed Venus Williams was let off the hook by Daniela Hantuchova in their match. The Slovak served for the first set three times only to lose it on a tiebreak.

American Williams made the most of the reprieve, romping through the second set for a 7-6 (7-0) 6-2 win. Her sister Serena, top seed in the women's draw, also flirted with danger before overcoming Russian Elena Likhovtseva 6-1 4-6 6-3 to secure a place in the last 16.

Hewitt struggled to find his service rhythm throughout the match and his misery was compounded by his inability to cope with Pavel's powerful ground strokes.

Hewitt served 10 double faults during the match, the most costly of which came on Pavel's fifth match-point. After going a set and 4-2 down, Hewitt appeared poised to pull of one of his trademark comebacks when he broke back for 4-5. However, his serve faltered again as Pavel completed a memorable victory.

Capriati, who is competing in her third tournament of the season after missing the Australian Open with a back injury, failed to negotiate Daniilidou for the second time in a month. The American was also knocked out by the Greek in Dubai last month.

Former world number one Serena was playing only her second match after being sidelined for eight months with knee problems and her error-strewn performance against the world number 42 smacked of rustiness.

Serena, who underwent knee surgery in August, is playing her first tournament since winning Wimbledon last July. She next plays 17th-seed Maria Sharapova for a place in the quarter-finals.

In the men's draw, third seed Guillermo Coria came through a gruelling all-Argentine battle with a 6-2 3-6 6-3 win over Juan-Ignacio Chela.

Results:

Men's third round: Rafael Nadal (Spain) bt Roger Federer (Switzerland) 6-3 6-3; Todd Martin (U.S) bt Jurgen Melzer (Austria) 7-6 (7-4) 6-3; Fernando Gonzalez (Chile) bt Jiri Novak (Czech Republic) 6-4 6-2; Nicolas Kiefer (Germany) bt Robby Ginepri (U.S) 7-6 (7-3) 3-6 6-4; Sebastien Grosjean (France) bt Theirry Ascione (France) 6-3 4-6 7-6 (7-1); Andrei Pavel (Romania) bt Lleyton Hewitt (Australia) 6-4 7-5; Julien Benneteau (France) bt Ivan Ljubicic (Croatia) 7-6 (7-3) 6-1; Guillermo Coria (Argentina) bt Juan Ignacio Chela (Argentina) 6-2 3-6 6-3

Women's third round: Venus Williams (U.S) bt Daniela Hantuchova (Slovakia) 7-6 (7-0) 6-2; Elena Dementieva (Russia) bt Maria Sanchez Lorenzo (Spain) 6-4 6-3; Nathalie Dechy (France) bt Shenay Perry (U.S) 6-2 6-2; Jelena Dokic (Serbia & Montenegro) bt Kristina Brandi (Puerto Rico) 7-5 6-4; Paola Suarez (Argentina) bt Magui Serna (Spain) 6-4 6-2; Maria Sharapova (Russia) bt Anna Smashnova-Pistolesi (Israel) 7-5 6-2; Eleni Daniilidou (Greece) bt Jennifer Capriati (U.S) 6-2 6-4; Tatiana Golovin (France) bt Jelena Jankovic (Serbia & Montenegro) 6-7 (4-7) 6-1 7-5; Karolina Sprem (Croatia) bt Maria Vento-Kabchi (Venezuela) 4-6 6-3 6-0; Alicia Molik (Australia) bt Silvia Farina Elia (Italy) 6-3 6-7 (5-7) 6-4; Francesca Schiavone (Italy) bt Lisa Raymond (U.S) 6-3 6-4; Svetlana Kuznetsova (Russia) bt Aniko Kapros (Hungary) 2-6 7-6 (7-4) 6-3; Nadia Petrova (Russia) bt Emilie Loit (France) 6-1 6-3; Gisela Dulko (Argentina) beat Vera Douchevina (Russia) 7-6 (7-4) 6-4; Serena Williams (U.S.) bt Elena Likhovtseva (Russia) 6-1 4-6 6-3; Jill Craybas (U.S.) bt Vera Zvonareva (Russia) 6-2 3-6 6-3. -Reuters