Sergio Henao and Ian Boswell finished second and third on Mt Baldy during a thrilling queen stage at the Tour of California.

The pairing pushed hard up the famous climb after Team Sky had laid down a hard pace on both the lead-up to the mountain and its early slopes.

After Boswell's acceleration saw the lead group splinter, Henao made his move with 5.5 kilometres to go, jumping clear of the pack and was immediately followed by Julian Alaphilippe (Etixx - Quick-Step).

The Frenchman continued his superb season by pushing onwards to take a solo victory, 23 seconds ahead of Henao and Boswell to move into the race lead.

Boswell worked his way back up to Henao ahead of the final kilometre to pace his team leader home, while Pete Kennaugh crossed the line in ninth to cap a consistent showing for the team.

Heading into the stage with a 28 second race lead, all eyes were on Peter Sagan (Tinkoff-Saxo) as he buried himself to remain in touch. Crossing the line 47 seconds back on Alaphilippe, Sagan lost the lead by a slender two seconds, setting up a thrilling finale in Los Angeles.

Boswell jumped up to seventh overall with one stage to go, 1:19 back while Kennaugh now sits ninth, 1:40 off the gold jersey.

The 128.7km queen stage always looked likely to reshape the GC and Team Sky set out their stall by putting the team on the front in the closing stages.

Taking it up at 35km to go with Nathan Earle, Danny Pate and Xabier Zandio, the men in black and blue began to set a fierce pace.

Philip Deignan and Christian Knees then took it up as the peloton started to thin out against a stunning backdrop, with Johann Van Zyl (MTN Qhubeka) the last of the day's breakaway contingent to be caught on the road with 21km to go.

With the lead group in tatters after Boswell upped the pace, a grandstand finish unfurled on the 15 switchbacks, with Alaphilippe bolstering his already growing reputation with victory.

"You have to say hats off to Alaphilippe today," admitted Sports Director Servais Knaven. "He was the strongest guy and he showed that on the final mountain. We had Sergio and Ian up there but he did a really strong ride.

"As a team the guys did a really good job. We controlled the race and made it hard. I think everyone was riding really well today.

"Ian was really strong and everyone is really happy to see him performing like this. He was able to help Sergio a bit in the final kilometre and it was a great ride.

"Sergio is third on GC now and we want to keep that of course. It's going to be a nice battle up front for the GC win tomorrow so we'll look forward to that."