TOUR DE FRANCE
Date: 4 July - 26 July
Coverage: BBC Sport website: text commentary of each stage and streamed BBC commentary of the last 90 minutes of each stage available; commentary on selected stages on BBC 5 Live sports extra
Nocentini is the first Italian to wear the yellow jersey for nine years
Italy's Rinaldo Nocentini grabbed the yellow jersey on the first mountain stage of the 2009 Tour de France.
But Spaniard Alberto Contador looks poised to take the lead in the next few days after a dramatic late break.
His Astana team-mate Lance Armstrong came home 22 seconds behind Contador in a group with Britain's Bradley Wiggins.
Brice Feillu of France won the stage, a 224km trek from Barcelona to Andorra Arcalis, while former leader Fabian Cancellara dropped from contention.
Although the little-known Nocentini has the race lead for now, Contador is just six seconds behind after a breathtaking late move on the main group.
He moves above Armstrong, who is a further two seconds behind, while Wiggins is in fifth spot after an outstanding climbing performance kept him alongside the Tour's biggest names.
The first of three days of racing in the Pyrenees was also the longest stage in this year's Tour.
Feillu was part of a nine-man breakaway that escaped early in the day and he outlasted his rivals on the climb up Arcalis to the finish.
But the real drama was taking place down the road, where Contador produced an astonishing show of strength to decimate a group containing Armstrong and most of the other contenders for the General Classification.
A burst of acceleration inside the final two kilometres took the Spaniard clear of riders like Andy Schleck, Wiggins and two-time runner-up Cadel Evans, while Armstong could not - or would not - keep up.
Contador's break underlined the rivalry that exists between the 2007 champion and seven-time winner Armstrong as they jostle for position - both as Astana team leader and for the right to wear the yellow jersey.
Armstrong insisted afterwards that he chose to stay with Schleck rather than trying to catch Contador because to do so would have helped his rivals and undermined Astana's chances.
"When you've got a rider away, my obligation is to the team," said Armstrong. "I had to stay on his wheel. You just got to stay on his wheel.
"That's not my specialty, but it's not bad at all - all things considered.
"Overall, I feel pretty good. I'm not as tired as I thought I'd be. Things didn't quite go according to plan that we set up earlier, but it didn't matter. It was a fine day overall."
Contador played down the significance of his break in the stage's closing kilometres.
"It was not a coup," said Contador. "I had nothing special in mind. But I'm on my terrain and I really enjoyed riding in the mountain so close to home."
And Contador insisted his lead over Armstrong did not mean much.
"It does not make me the team leader. Only the race will decide on the leader," he said.
Contador's impressive display was not quite enough to put the 2007 Tour winner back in yellow as Nocentini - also part of the original breakaway - was just quick enough to take the overall lead.
The AG2R rider, who is competing in his first Tour, becomes the first Italian in nine years to lead the race and said: "I am very happy. I came here to win a stage but I finish today with the maillot jaune."
Nocentini replaces Swiss star Cancellara, who had worn yellow for seven successive days.
Cancellara recovered superbly from two punctures earlier in the day, catching up with the peloton with some daring descending, but he lost touch again on the ascent to the finish line and is now more than five minutes back.
France's Sebastian Joly pulled out midway through the stage to become the fourth rider to retire from this year's Tour.
Stage seven result:
1. Brice Feillu (Fra/Agritubel) 6 hours 11 minutes 31 seconds
2. Christophe Kern (Fra/Cofidis) + 5secs
3. Johannes Froehlinger (Ger/Milram) +25
4. Rinaldo Nocentini (Ita/AG2R) + 26
5. Egoi Martinez (Spa/Euskaltel) + 45
6. Christophe Riblon (Fra/AG2R ) + 1min 5secs
7. Jerome Pineau (Fra/Quick-Step) + 2mins 32secs
8. Jose Ivan Gutierrez (Spa/Caisse d'Epargne ) + 3mins 14secs
9. Alberto Contador (Spa/Astana) + 3mins 26secs
10. Cadel Evans (Aus/Silence-Lotto) + 3mins 47secs
12. Bradley Wiggins (GB/Garmin) "
15. Lance Armstrong (USA/Astana) "
67. Fabian Cancellara (Swi/Saxo Bank) + 9mins 16secs.
95. Charlie Wegelius (GB/Silence) + 10mins 21secs
137. Mark Cavendish (GB/Columbia) + 28mins 29secs
163. David Millar (GB/Garmin) "
1. Rinaldo Nocentini (Ita/AG2R) 25 hours 44 minutes 32 seconds
2. Alberto Contador (Spa/Astana) +6 secs
3. Lance Armstrong (USA/Astana) + 8
4. Levi Leipheimer (USA/Astana) +39
5. Bradley Wiggins (GB/Garmin) +46
15. Carlos Sastre (Spa/Cervelo) + 2minutes 52secs
39. Fabian Cancellara (Swi/Saxo Bank) +5mins 37secs.
95. Charlie Wegelius (GB/Silence) + 21mins 46 secs
110. David Millar (GB/Garmin) + 27mins 18 secs
121. Mark Cavendish (GB/Team Columbia) + 28 min 23secs