Valtteri Bottas was challenged to prove his reaction times on Monday following accusations he made a jump start at the Austrian Grand Prix.
The Mercedes driver flew off the grid at the Red Bull Ring on his way to victory and, although he was cleared of any wrongdoing, Ferrari's Sebastian Vettel - who started second - still had his doubts after the race.
According to the FIA, Bottas "made an exceptionally accurate and fortuitous judgement call, anticipating the moment the lights went out with great precision. Any movement prior to the moment the lights went out was within the tolerances allowed."
But for the avoidance of doubt, Bottas responded to a request from a Twitter user to test his reactions by halting the stopwatch on his phone as close to five seconds as he could.
Very impressive, Valtteri!