Lewis Hamilton's Mercedes team are preparing for Sunday's season-opening Australian Grand Prix uncertain if they are still the all-conquering force of Formula One.
Mercedes have won 51 of the last 59 grands prix en route to claiming three consecutive drivers' and constructors' championships during an unprecedented reign of dominance.
But changes to the sport's technical rulebook during the off-season has offered fresh hope to Mercedes' rivals, and it is not clear whether the Brackley-based team will still be the ones to beat in Albert Park this weekend.
Indeed Ferrari, whose challenge will be spearheaded by four-time world champion Sebastian Vettel, enjoyed eight strong days of pre-season testing in Barcelona.
And the famous Italian team, who failed to register a single victory last year and are without a drivers' champion in more than a decade, will head into the new campaign cautiously optimistic.
"What we've seen from Barcelona is that the margins at the front of the field have shrunk," Mercedes boss Toto Wolff said on Monday.
"We'll see how that pans out in Melbourne, because we still don't know about the fuel loads, weights or power settings of the other cars. As the old saying goes, it is when the flag drops that the bull**** really stops.
"But we have done the best job we possibly could over the winter and, if we are not the fastest in Melbourne, then it's about finding out why and what needs to be done to get us back to that top spot. It's a challenge we will take on with great motivation and energy."
The cars are wider, faster and more aggressive in their design this year in a bid to spice up a show dominated by Hamilton's Mercedes team.
But in the sport's long history, no constructor has been able to stay on top of the sport following a major overhaul of its regulations. A point Wolff was keen to stress.
"We have been very successful over the last three years through stable rules - but no team has ever maintained its success over such a big regulation change before," he added. "In a way, it's just what the doctor ordered. To have such a challenge is good for the team.
"There is an art to managing expectations. You must not set them too low but you must also keep them under control. With new regulations, everyone starts with zero points.
"It provides opportunities as well as risks for every team on the grid. We enter 2017 with that mindset. We take every one of our rivals seriously and respect every team's ability to find that magic bullet."
Hamilton, who arrived in Melbourne on Monday night, will be partnered by Finnish driver Valtteri Bottas this year following Nico Rosberg's retirement.
Hamilton, 32, is aiming to become the first British driver to win four championships.