Andy Schleck wins difficult stage 18

The Luxembourg climber, runner-up to Contador in 2009 and 2010, reached the top of the 2,645-metres Galibier pass -- the highest ever finish to a Tour stage -- on his own but his efforts were not enough to dislodge Thomas Voeckler from the yellow jersey.

Contador's hopes of a fourth Tour triumph suffered a huge blow as he could only trail in 15th - 3:50 behind Schleck to remain seventh overall and needing to produce something special in the closing stages if he wants to celebrate in Paris again on Sunday.

Frenchman Voeckler, his face distorted by pain and suffering, crossed the line 2:20 adrift to retain his lead which now stands at just 15 seconds over the stage winner.

The other strong man in this gruelling 200.5-km ride into headwinds from the Italian town of Pinerolo was Australian Cadel Evans, who led the chase behind Schleck in the final ascent almost on his own, with Voeckler on his heels.

Third over the line behind Andy's brother Frank, the 2009 world champion lies fourth overall, 1:12 behind Voeckler, an ideal position for Evans given his time trial skills.

The Tour unfolds in the next two days with a compact but scary ride to l'Alpe d'Huez on Friday, followed by a hilly individual time trial in Grenoble.

Leopard Trek team leader Andy Schleck stunned the rest of the field by attacking early in the second classic climb of the day, the Izoard pass, when everybody was expecting the big battle to take place in the final ascent to the Galibier.

The profile of the stage seemed to favour the chasers as Schleck's attack took place 60 kilometres from the line and against headwinds.

While the Luxembourg rider found support from his Belgian team-mate Maxime Monfort, who had been part of an earlier break and waited for his leader, his opponents obviously underestimated his strength and thought they could make up for lost time in the valley.

Reluctant to send their team-mates to the front of the bunch to lead the chase, they remained helpless as the gap gradually increased.

For the time being, it remains on Voeckler's back, the first time in more than 20 years that a Frenchman has led the Tour three days before the finish in the French capital.

Tour de France, Stage 18, Pinerolo to Galibier Serre-Chevalier
1. Andy Schleck (Lux) Leopard Trek - 6:07:56
2. Fränk Schleck (Lux) Leopard Trek - at two minutes seven seconds
3. Cadel Evans (Aus) BMC Racing Team - at two minutes 15 seconds
4. Ivan Basso (Ita) Liquigas - at two minutes 18 seconds
5. Thomas Voeckler (Fra) Team Europcar - at two minutes 21 seconds
6. Pierre Rolland (Fra) Team Europcar - at two minutes 27 seconds
7 Damiano Cunego (Ita) Lampre - ISD - at two minutes 33 seconds
8. Rein Taaramae (Est) Cofidis, Le Credit En Ligne - at three minutes 22 seconds
9 Thomas Danielson (USA) Team Garmin-Cervelo - at three minutes 25 seconds
10. Ryder Hesjedal (Can) Team Garmin-Cervelo - at three minutes 31 seconds
15. Alberto Contador (Spa) Saxo-Bank Sungard - at three minutes 50 seconds

General classification after Stage 18:
1. Thomas Voeckler (Fra) Team Europcar - 79:34:06
2. Andy Schleck (Lux) Leopard Trek - at 15 seconds
3. Fränk Schleck (Lux) Leopard Trek - at one minute 08 seconds
4. Cadel Evans (Aus) BMC Racing - at one minute 12 seconds
5. Damiano Cunego (Ita) Lampre - at three minutes 46 seconds
6. Ivan Basso (Ita) Liquigas - same time
7. Alberto Contador (Spa) Saxo-Bank Sungard - at four minutes 44 seconds
8. Samuel Sanchez (Spa) Euskaltel - at five minutes 20 seconds
9. Thomas Danielson (USA) Team Garmin-Cervelo - at seven minutes 08 seconds
10. Jean-Christophe Peraud (Fra) AG2R La Mondiale - at nine minutes 27 seconds