Sir Bradley Wiggins retained the lead in the Tour of California for a fourth consecutive day to hold an advantage of 28 seconds with three stages to go.
The 34-year-old Briton and Rohan Dennis, who is second in the overall standings, finished 12 seconds behind stage five winner Taylor Phinney.
The American took the 172.9km (107.4 mile) leg after a solo breakaway in three hours 59 minutes 33 seconds.
Slovakia's Peter Sagan was second, with Australia's Matthew Goss third.
The stage ran from Pismo Beach to Santa Barbara, while Friday will take riders from Santa Clarita to Pasadena on a 151.8km (94.3 mile) leg with a climb to a mountain-top finish.
1. Taylor Phinney (USA/BMC) 3:59:33
2. Peter Sagan (Svk/Cannondale) +12secs
3. Matthew Goss (Aus/Orica) same time
4. Jasper Stuyven (Bel/Trek) same time
5. Kiel Reijnen (USA/United Healthcare) same time
1. Bradley Wiggins (GBR/Sky) 17:53:36
2. Rohan Dennis (Aus/Garmin) +28"
3. Tiago Machado (Por/Endura) +1:09
4. Lawson Craddock (USA/Giant Shimano) +1:25
5. Adam Yates (GBR/Orica) +2:14