The 19-year-old Briton became the youngest starter of a Formula E race when he competed in Saturday’s Monaco E-Prix, having only been told 20 minutes before the second practice session that he would be competing.
This was after regular McLaren driver Bird suffered a high-speed off at Sainte Devote in the day’s earlier FP1 session that left him with a broken bone in his left hand, meaning Barnard got the call-up as the team’s reserve driver.
“The first initial reaction was a lot of nerves, a lot of tension,” Barnard told Autosport about being informed he would be racing.
“I then had to run to sign-on to actually make sure that I could drive then it was basically throw my suit on and get in the car. So not much time to think about it.
“There was not really time to go through things and worry about it.”
Having only done one 30-minute session before qualifying, where he finished last in his group but only 1.730s off the leading time, Barnard put in an assured drive to eventually finish 14th out of 20 finishers.
Having only ever done Formula E rookie practice outings with McLaren, the latest coming ahead of the Misano E-Prix where he topped the session, Barnard believes he adapted well given the circumstances.
“The first five laps I kind of backed off a little bit and kind of took my time, saved as much energy as I could,” said Barnard, who raced at Monte Carlo last season in Formula 3.
“I’m not really sure if that was the plan but it was the most comfortable for me at the time and in hindsight, I think it was probably the best thing to do.
“There’s nothing you can do to prepare for one of these races, you just have to get thrown in at the deep end and I think I adapted fairly well.
"For sure there’s some things that I want to review and learn and do better for potentially if there is a next time.”
McLaren confirmed that Bird "will require further treatment" to his injured hand but there has been no update on whether he will need surgery, or if he will miss the next event in Berlin.
Barnard was set to compete in the rookie test following the Berlin E-Prix double-header next month but will be unable to do so having already made his Formula E debut.
However, the full-time F2 racer will almost certainly be called in to replace Bird should the 12-time Formula E winner not be able to recover in time.
