Tour de France: Contador suffers in the Pyrenees after Thomas's dramatic climb

Alberto Contador's status as cycling's No 1 took its biggest step backwards in four years yesterday on the slopes of Luz Ardiden – on the same day that Geraint Thomas came the closest a Briton has been to taking a high mountain Tour stage since Robert Millar in 1989.

As favourites Cadel Evans, Ivan Basso and the Schleck brothers piled on the pressure, Contador all but crumbled on the final kilometre of the summit finish, complaining of a knee injury that has dogged him since a crash on stage nine.

In time terms, the damage was minimal, just 13 seconds on Andy Schleck, the rider who has run him the closest for the last two years, and 33 seconds on Andy's brother, Frank. However, psychologically, the rare sight of Contador flailing away on a crucial mountain stage will be exactly the kind of motivation his rivals will need to challenge the triple Tour winner.

Beleaguered even before the Tour started by the ongoing saga of his positive test for clenbuterol in last year's race, and with a 100-second deficit after a crash on stage one, Contador complained afterwards that he had been feeling rough since the Tourmalet, the second of the three big climbs of the day.

Even so, when the race emerged above the treeline on Luz Ardiden, the Spaniard could still respond to most of the attacks made by Andy Schleck and Evans' driving accelerations. However, when Frank Schleck, Andy's brother and team-mate, made a third major dig on the never-ending series of hairpins close to the summit, the Spaniard was in trouble.

Worse was to come, as double Tour of Italy winner Basso edged up the pressure even higher in the final kilometre, and as the leading favourites dived round the last corner, Contador was nowhere to be seen.

He finally trailed across the finish line in eighth place, so exhausted that he all but fell off his bike and grabbed the corner of the podium to keep himself from crashing. The Spanish – or strictly speaking, the Basques – still had something to celebrate thanks to 2008 Olympic road race champion Samuel Sanchez taking the stage win after he blasted off at the foot of the climb in the company of Belgium's Jelle Vanendert.

However, Contador's defeat – his most important in the Tour de France since 2007 – meant that in the bigger picture, the Spaniard is clearly in trouble. "It was finally a good day for me because my knee hurt since the Tourmalet and I didn't lose more time," a resolutely upbeat Contador, now seventh overall at four minutes behind leader Thomas Voeckler, said afterwards.

"Andy Schleck and Frank Schleck have improved their chances, Evans and Basso are stronger now and I will have to race intelligently," he added.

If Contador's defeat on the slopes of Luz Ardiden looked distinctly ominous, when Thomas was finally reeled in a little earlier it had all the feel of a glorious surrender – and holds great hope for the Welshman's climbing potential in the future.

On the attack since the second kilometre in a break of five – and rightly awarded the Most Combative Rider prize – the Sky rider was the last of the move to be caught. In a dramatic day out for the Briton, he skidded and fell twice shortly after the summit of the first climb, but was uninjured and able to make his way back into the break – and keep going.

With three minutes lead at the foot of the Tourmalet, Thomas said: "I didn't think we would have enough of a gap to win, but you've to try. When they caught us with 7km to go, I thought it wasn't too bad, but it still took me half an hour to get up the bloody thing."

As for his double-tumble, Thomas was phlegmatic about it, saying: "There was something on the road and I ended up crashing. It looked a bit of a drop so I thought, 'I better crash now before going off down there'. The second one was just stupid. I think I had a bit of mud on my tyres and couldn't slow down quickly enough."

If Voeckler provided a smile for the French on Bastille Day by riding way above expectations and clinging on to yellow, Contador had a rough day, but survived – just. "It's definitely not all over for Alberto," Andy Schleck said. "If that's a bad day, then I dread to see what he'll be like on a good one."

Standings

Stage 12 (Cugnaux Luz-Ardiden, 209km):

1 Samuel Sanchez Gonzalez (Sp) Euskaltel-Euskadi

2 Jelle Vanendert (Bel) Omega Pharma-Lotto

3 Frank Schleck (Lux) Leopard Trek

4 Ivan Basso (It) Liquigas-Cannondale

5 Cadel Evans (Aus) BMC Racing Team

6 Andy Schleck (Lux) Leopard Trek

7 Damiano Cunego (It) Lampre - ISD

8 Alberto Contador Velasco (Sp) Saxo Bank Sungard

9 Thomas Voeckler (Fr) Team Europcar

10 Pierre Rolland (Fr) Team Europcar

Selected others

36 Geraint Thomas (GB) Sky Procycling

139 Ben Swift (GB) Sky Procycling

148 David Millar (GB) Team Garmin-Cervelo

153 Mark Cavendish (GB) HTC-Highroad

Overall

1 Thomas Voeckler (Fr) Team Europcar 51hr 54min 44sec

2 Frank Schleck (Lux) Leopard Trek at 1min 49sec

3 Cadel Evans (Aus) BMC Racing Team at 2.06

4 Andy Schleck (Lux) Leopard Trek at 2.17

5 Ivan Basso (It) Liquigas-Cannondale at 3.16

6 Damiano Cunego (It) Lampre - ISD at 3.22

7 Alberto Contador Velasco (Sp) Saxo Bank Sungard at 4.00

8 Samuel Sanchez Gonzalez (Sp) Euskaltel-Euskadi at 4.11

9 Thomas Danielson (US) Team Garmin-Cervelo at 4.35

10 Nicolas Roche (Rep Ire) AG2R La Mondiale at 4.57

Selected others

25 Geraint Thomas (GB) Sky Procycling at 10.31

60 David Millar (GB) Team Garmin-Cervelo at 37.47

118 Mark Cavendish (GB) HTC-Highroad at 1.17. 57

124 Ben Swift (GBr) Sky Procycling at 1.19.58