Lewis Hamilton will serve at least a 15-place grid penalty in Sunday's Belgian Grand Prix after taking on a fresh engine.
The reigning world champion, who leads his Mercedes team-mate Nico Rosberg by 19 points in this year's title race, will start no higher than 16th after his team confirmed he has taken on a new turbo and MGU-H, exceeding the five he is allowed before a penalty is enforced.
The penalty has been looming over the British driver after he encountered a number of engine problems in the opening rounds of the season.
Hamilton's Mercedes team had been weighing up whether to take the grid drop here at Spa or at next Sunday's Italian Grand Prix, with both circuits expected to offer him the best chance of fighting back through the field.
But after confirming the penalty on Thursday, replacement components were fitted on to Hamilton's engine in opening practice.
Under the sport's complicated rules, he could yet drop to the back of the field should Mercedes opt to fit additional parts to Hamilton's engine before Sunday's race.
No driver in the history of the sport has ever won from last on the grid. John Watson, the Belfast-born former McLaren driver, holds the record of winning from the lowest start slot after lining up in 22nd on the grid of 26 competitors before winning the 1983 United States Grand Prix at Long Beach.
But Hamilton, speaking on Thursday, did not rule out claiming what would be a remarkable victory on Sunday.
''In terms of winning that is the goal, but it is going to be very, very hard,'' said Hamilton, who is just one win shy of 50 career victories.
''I will do everything I can to minimise the impact that the penalty will have, and beyond that I plan to continue with the momentum I had before the break.''
Hamilton crossed the line in seventh at this year's Chinese Grand Prix after he was forced to start from the pit lane following an engine failure in qualifying.
A fire in qualifying at the Hungarian Grand Prix in 2014 also saw Hamilton fight back from last to third. On that day his comeback was aided by rain, but it is set to be dry for Sunday's race.
''It is going to be harder than it was to climb through the field but I will do everything I can,'' Hamilton, 31, added. ''It is about minimising the damage from taking the penalty."