Sierra made the most of good positioning in the final, coming off the wheel of Alexis Ryan (Canyon-SRAM) to propel her way to victory on the streets of Sacramento.
It looked like Canyon-SRAM had nailed their final leadout perfectly as they led the peloton into the final but Ryan had to take up the sprint maybe a bit too early.
That gave Sierra the box seat and the Cuban sprinter made the most of the opportunity, claiming her first World Tour win in style.
Earlier, an aggressive race had seen a number of teams try to break away and force the issue on the fast course but the teams of the sprinters proved to be very attentive, quickly shutting down moves.
With the general classification all but decided on the previous day's queen stage, Katie Hall (UnitedHealthcare) enjoyed a stress-free finish to her Tour. It was a stark contrast from last year where she lost the Tour of California on the final day to Anna van der Breggen (Boels-Dolmans) in the fight for bonus seconds.