The 27-year-old Briton, Lewis Hamilton who has finished third three times this season for McLaren and lies second in the embryonic drivers' title race, said the tussle to win the Spanish Grand Prix is wide open.
Refreshed after a two-week break following the Bahrain Grand Prix, the 2008 world champion will go into next Sunday's race at the Circuit de Catalunya seeking his first win of the year to overhaul defending double champion Sebastian Vettel.
German Vettel leapt to the top of the early-season standings with his first triumph of the season for Red Bull in Bahrain.
"It is all so hard to read," said Hamilton. "It is so difficult to predict who will be at the front because of the form this year.
"We did well in winter testing at Barcelona and that was good for us, but they (Red Bull) won last year's race.
"We had a great race in Spain last time and I pushed Sebastian all the way to the finish. On top of that, I feel we have a comparatively strong car this year so I am hoping we will have another strong race.
"But the way it has been going this year, who knows? It is so difficult to predict this season."
Hamilton and his McLaren team-mate and fellow-Briton Jenson Button, the 2009 champion, will fly to Barcelona confident that they have a package to set the pace after a strong start to the year.
But he knows that any repeat of the failings the team has shown recently with their pit-stops, or a technical problem like the imperfect choice of gear ratios last year in Spain, could leave him struggling.
As often, Hamilton indicated that he believes he will be fast enough in qualifying, but could struggle for race performance - and pointed at a need for good overtaking to take advantage of strong car potential.
"It'll be interesting to see how straightforward overtaking will be this year. It's always been a tough place for passing - as I found out last year - but I really hope that our DRS (Drag Reduction System) and KERS (Kinetic Energy Recovery System) combined will make it a little easier," he explained.
"I think it's going to be one of the toughest tracks of the year for overtaking, but I'll be hoping for a strong performance in qualifying in order to make it as straightforward as possible in the race."
While most of the top teams and drivers were in Mugello, Italy, this week for an official in-season test session, Hamilton and Button were rested - giving test drivers Gary Paffett and Oliver Turvey a chance to do their work - ahead of next week's key race, the fifth of this year's 20-race season.
McLaren team boss Martin Whitmarsh said he believed the Spanish race would give a good indication of the relative strengths of the teams and their prospects.
He said: "Barcelona should give all the teams a clearer understanding of how the tyres behave in what's likely to be a 'typical' European race climate, but there will still be plenty to learn."
Like most close observers, he will expect a resurgence from Ferrari in Spain where two-time champion Spaniard Fernando Alonso will be bidding to rediscover his best form in front of his home fans - and to prove that the Italian team have what it takes to mount a title challenge this year.
"You can never right them off," said Hamilton. "It is going to be very tight all the way this year."