The 31-year-old Boels–Dolmans rider sprinted up the final climb of the 72-mile clockwise loop of Lake Tahoe to beat Wiggle High5’s Johansson by four seconds with a time of 3 hours 05min 09sec.

Armstrong of Twenty16 - Ridebiker ended a further six seconds back, showing excellent road racing form with a third place finish. 

Podium Ambition’s Sarah Storey formed the major breakaway of the day, but the peloton picked up the chase with 25 kilometres remaining as the Briton struggled to deal with the strong winds.  

Storey, the five-time Paralympic gold medallist, was caught approximately 10km from the finish and it was Boels-Dolmans, winners of five of the last seven Women's WorldTour races, that ultimately took control.

Guarnier followed team-mate and compatriot Evelyn Stevens into the final corner before overtaking Johansson and Armstrong.

"We didn't purposefully give her a lot of a lead," said Guarnier in reference to Storey's advantage. 

"She was super strong and it was a really great ride by her, but it did put a lot of pressure on us at the end of the day.

"The girls sacrificed a lot to bring that back."

Armstrong identified patience as the key to her impressive performance today.

"Being in the good position I was is a credit to my team," she said.

"Once we got to the climb the job was mine and I had to be really patient.

"I kept hearing 'patience' in the radio and it's not my forte to be patient.

"Typically, I'm the first one off and the first one dropped.

"So today I learned something new."

Racing is due to continue tomorrow with a team time trial.