ST ETIENNE, France, July 15 - Belgian champion Ludo Dierckxsens earned his first Tour de France victory at the age of 34 on Thursday as he captured the 11th stage from Bourg d'Oisans in a bold solo breakaway.

The veteran rider from Antwerp parted company with five breakaway companions 25 kms from the finish of the 198.5-kms ride and raced alone to gain the most prestigious victory of his career in just over four-and-a-half hours.

American Lance Armstrong retained the race leader's yellow jersey despite finishing in the main peloton more than 22 minutes later.

Dierckxsens, who turned professional only at the age of 30, had won just two major races in the past -- Paris-Bourges last year and the Belgian championship one week before the Tour.

The bald Belgian, who worked as a mechanic before turning pro, made his move shortly before the summit of the demanding Croix de Chaubouret climb.

After his attack, France's Laurent Lefevre, who had broken away first after 80 kms, lost ground while Russian Dimitri Konyshev, Kazakh Alexander Vinokourov, Italian Wladimir Belli and Belgian Rik Verbrugghe were left chasing behind.

The four were never able to bridge the gap and Konyshev, who was the first Russian to win a Tour stage nine years ago, had to be content with outsprinting Vinokourov for second place, one minute and 26 seconds behind Dierckxsens.

It was the first successful long solo breakaway of this year's Tour though Armstrong and Italian Giuseppe Guerini have each won an Alpine stage on their own after attacking in the last few kilometres.

Armstrong's U.S. Postal team mates let the six breakaway riders have their day as none of them posed any threat in the overall standings.

Vinokourov, the best-placed of the lot, was 43 minutes behind Armstrong at the start.

"It's a dream come true," said Dierckxsens. "I became Belgian champion two weeks ago and now I win this. It's incredible.

"I was 30 when I turned pro and this is only my second year in a big team. But I feel great and the Belgian champion jersey gave me extra motivation."

Asked if being a professional rider was harder than working as a mechanic, he said: "No. It is a very hard job too." Friday's 12th stage leads the 159 riders left in the race from St Galmier to St Flour over 201.5 kms with a steep two-kms climb at the finish.

Tour de France 11th stage placings 

ST ETIENNE, France, July 15 - Placings in the 11th stage of the Tour de France over 198.5 kms from Le Bourg d'Oisans on Thursday: 

1. Ludo Dierckxsens (Belgium) Lampre four hours 34 minutes and three seconds
2. Dimitri Konyshev (Russia) Mercatone Uno one minute and 26 seconds behind 3. Alexandre Vinokourov (Kazakhstan) Casino 
4. Wladimir Belli (Italy) Festina all same time 
5. Rik Verbrugghe (Belgium) Lotto 1:33 

6. Laurent Lefevre (France) Festina 3:53 
7. Riccardo Forconi (Italy) Mercatone Uno 5:07 
8. Erik Zabel (Germany) Telekom 22:18 
9. Robbie McEwen (Australia) Rabobank 
10. Gianpaolo Mondini (Italy) Cantina Tollo 

11. Christophe Capelle (France) Big Mat 
12. Lars Michaelsen (Denmark) La Francaise de Jeux 
13. Silvio Martinello (Italy) Polti 
14. Stuart O'Grady (Australia) Credit Agricole 
15. Francois Simon (France) Credit Agricole 

16. Peter Wuyts (Belgium) Lotto 
17. Sebastien Hinault (France) Credit Agricole 
18. Stephane Barthe (France) Casino 
19. Alexei Sivakov (Russia) Big Mat all same time 
20. Richard Virenque (France) Polti 22:21

Overall standings in the Tour de France after 11 stages on Thursday: 

1. Lance Armstrong (U.S.) U.S. Postal 51 hours 10 minutes and 28 seconds 
2. Abraham Olano (Spain) ONCE seven minutes and 42 seconds behind 
3. Alex Zuelle (Switzerland) Banesto 7:47 
4. Laurent Dufaux (Switzerland) Saeco 8:07 
5. Fernando Escartin (Spain) Kelme 8:53 

6. Virenque 10:01 
7. Pavel Tonkov (Russia) Mapei 10:18 
8. Daniele Nardello (Italy) Mapei 10:56 
9. Giuseppe Guerini (Italy) Telekom 10:57 
10. Angel Casero (Spain) Vitalicio Seguros 11:11 

11. Benoit Salmon (France) Casino 12:30 
12. Christophe Moreau (France) Festina 12:51 
13. Andrea Peron (Italy) ONCE 13:30 
14. Kurt van de Wouwer (Belgium) Lotto 16:14 
15. Mario Aerts (Belgium) Lotto 17:31 

16. Bo Hamburger (Denmark) Cantina Tollo 17:47 
17. Manuel Beltran (Spain) Banesto 18:27 
18. Stefano Garzelli (Italy) Mercatone Uno 19:07 
19. Tyler Hamilton (U.S.) U.S. Postal 19:12 
20. Carlos Contreras (Colombia) Kelme 19:58