Lewis Hamilton fears he faces an uphill task to land his Mercedes on pole position for the Azerbaijan Grand Prix following Friday's troubled practice.
Hamilton ended the day at the Baku City Circuit well off the pace in a lowly 10th after he failed to deliver an error-free lap during the second session.
Red Bull's Max Verstappen led the way with Valtteri Bottas, driving the sister Mercedes, in second and Sebastian Vettel, the man who leads Hamilton in the championship by 12 points, fifth.
"It was a difficult day out there," said Hamilton. "This circuit is a tough one and we had a few challenges that we tried to work through today.
"We've clearly still got lots of work to do ahead of qualifying, but Valtteri's time in second practice looked promising, so there is obviously pace in the car, which is encouraging.
"Now it's just a case of getting our heads together tonight to work out exactly how to extract that pace across the entire weekend."
Hamilton's difficulties marked a topsy-turvy day of action on the streets of Azerbaijan's capital city with Verstappen fastest in both sessions, while both under-fire British driver Jolyon Palmer and Force India's Sergio Perez crashed into the wall at Turn Eight.
Hamilton, meanwhile, also poured scorn over his own suggestion that he could stun the sport by retiring at the end of the season.
The Briton, this year chasing a fourth world title, which would elevate him ahead of his boyhood hero Ayrton Senna and into the pantheon of the sport's all-time greats, instead spoke of hunting down Juan Manuel Fangio's haul of five championships.
He is perhaps even targeting Michael Schumacher's record of seven.
"I could easily do another three-year contract if I wanted to and I reckon I could go on for another one after that,'' said Hamilton, whose £30million-a-year-deal with Mercedes expires next season.
"People ask me 'what's motivating you?' I still want more. I still want two championships.
"I always wanted to emulate Senna, but then you set your sights on new goals, new challenges and new horizons so that's really the discovery phase.
"When I think about Fangio, five titles sounds pretty good. Vettel's only one away from five so if I get to five he could easily equal that, and then I've got to get six.
"The human race is a greedy kind, and we always want more. For me, it's not like I want more, but I feel like I have more potential, and I feel like it's a constant journey to discover just what that potential is. There's no real limit to what we can achieve. The limit is a state of mind.''