The Racing Steps Foundation-backed teenager, running with the Hitech GP team throughout 2016, battled throughout the early stages of the session on a drying track after rainfall had soaked the track during the earlier final Free Practice.
Barnicoat managed 10 timed laps, with a best time of 1m 24.545s, which placed him inside the top three places. But the chequered flag fell just as Barnicoat was heading over the start/finish line to begin his final lap.
That enabled drivers in front to set one last quick time, and relegate Barnicoat to a starting position for Saturday’s opening race of fifth.
“To start my first ever Formula 3 race in fifth position is a pretty solid platform to work from,” Barnicoat said. “The track was just getting better and better throughout the session as it dried up.
“I was going well and improving every lap, so it was disappointing to be caught out by the chequered flag. I felt that I could have gone even better, by up to half a second, if I’d been able to bank that final lap.”