California - American Dave Zabriskie maintained the overall lead while France's Sylvain Georges survived the gruelling mountain terrain to win the sixth stage of the Tour of California on Friday.
Georges (Ag2r-La Mondiale), 28, claimed his fifth career victory after pedalling alone in the lead for the final 48 kilometres (30 miles) en route to his title in five hours, seven minutes and six seconds.
"The most difficult thing about the final kilometres was in my head," Georges said. "I hurt everywhere. I was starting to go cross-eyed and getting cramps, but I was able to focus and fight through it.
"It was the hardest 15k of my life."
Peter Sagan of Slovakia finished second by 28 seconds in the stage that featured four different climbs. Countryman Peter Velits finished third. Sagan won the first four stages.
Zabriskie (Garmin-Barracuda) took the race lead with a dominating individual time trial win in stage five.
He finished 21st in the main field and maintained a 34-second race lead over fellow American Tejay van Garderen.
Georges formed part of an escape group after 1.5 kilometres (0.9 miles) but found himself alone at the top of the final climb of the day.
He held on for the win despite a forceful three-man counter attack, containing Wilco Kelderman, Pieter Weening and Jeremy Vennell, that eventually got swept up in the final kilometres.
"For me it's the most beautiful victory of my career," said Georges. "I've never arrived solo for victory like this and it was incredibly special. It's a beautiful race with all the big teams."
Competitors raced under blue skies but gusty winds buffetted the riders at the start of the stage in the desert city of Palmdale and along the open mountain roads of the Angeles National Forest.
Stage seven will feature an even tougher mountain climb as the riders start in Ontario, California then head into the San Gabriel Mountains, where they travel along the Glendora Ridge Road to the finish at the parking lot of the Mt. Baldy ski resort.
Top finishers of Friday's 186.3-kilometre sixth stage in the Tour of California:
1 Sylvain Georges (FRA) in 5hrs, 7mins, 6secs
2. Peter Sagan (SVK) at 28
3. Peter Velits (SVK) s.t.
4. Thomas Damuseau (FRA) s.t.
5. Tom Dumoulin (NED) s.t.
6. Greg Van Avermaet (BEL) s.t.
7. Romain Bardet (FRA) s.t.
8. Christopher Horner (USA) s.t.
9. Tejay Van Garderen (USA) s.t.
10. Robert Gesink (NED) s.t.
1. David Zabriskie (USA) in 25:37:05
2. Tejay Van Garderen (USA) 34
3. Robert Gesink (NED) 39
4. Peter Velits (SVK) 45
5. Andrew Talansky (USA) 48