Van Garderen (BMC Racing) won Wednesday’s time trial to enter the 196.5km trip to altitude in Stage 6 with a 23 second buffer on Bernal (Sky).
The roles, however, were reversed at the finish in South Lake Tahoe where Bernal celebrated a solo victory, pointing to the sponsor on his jersey as he crossed the line, to reclaim the overall lead.
The Colombian rookie pro has all but won the tour now, with van Garderen one minute and 25 seconds in arrears for second and Daniel Martinez (EF Education First –Drapac p/b Cannondale) two minutes and 14 seconds adrift in third.
“They [Sky] did an amazing race and we couldn’t match them. That was pretty much it,” Stewart told Cycling Central.
Even yesterday van Garderen was fully aware Sky’s tactic would be what it always is in a general classification hunt - assemble at the front, drill it on a key climb, decimate the field and invariably win alone.
Today that applied to the penultimate category one Daggett Hill summit, which followed five other climbs peppered along the route that started in the Folsom town Johnny Cash made famous.
Van Garderen had spent all his teammates before the final 20km and stayed glued to the Sky train as Sebastian Henao, Tao Geoghegan Hart and Bernal, like at Gibraltar Rd on stage two, set the tempo.
As the road continued to ramp up the main group exploded under the pace. Van Garderen put in an effort and bridged back to Geoghegan Hart and Bernal, but nearly as soon as he reached them Bernal attacked with 14km to go and stayed away.
Geoghegan Hart stuck with the chasers, including van Garderen, Martinez and Adam Yates (Mitchelton-Scott). After attacks and counter attacks, Brandon McNulty (Rally) and Rafal Majka (BORA-hansgrohe) bridged across with about 8km to go before chaos reigned again on the final kicker to the finish.
“When it came back together everyone saw we were in trouble and everyone wants to move up in GC so they’re all trying to attack each other and separate," said Stewart.
"It was a big mess. Bernal got out of the mess and just made everyone look silly."
“We knew Bernal would do it. We just didn’t think he’d go too far, and we also didn’t think Tejay would get isolated that much.”
Tomorrow’s sixth and final stage in Sacramento is designed for sprinters and is not likely to change the general standings.
Van Garderen’s campaign here can still be celebrated with the time trial victory at San Jose, his first individual triumph since the Giro d’Italia last year.
The 29-year-old is set to compete next at the Tour de Suisse before supporting Richie Porte in a yellow bid at the Tour de France.
“It’s not just you," said Stewart, "it’s 20 other people here that worked all two weeks for you. The riders gave everything.
"It’s a team achievement we can be happy with. We won a stage and we were competitive and on the podium, so you’ve got to be happy."
Coverage of the Tour of California continues for the final stage of the Mens and Womens events from 5.00 AM AEST on Sunday 20 May.