After starting on the bench against Richmond, O'Brien came onto the ground and within six minutes had kicked Essendon's first goal. About 15 minutes later he helped set up Scott Gumbleton's snap by grabbing the ball out of the air and passing it to the key forward.
And then, only moments later, the smooth moving left-footer marked on the half-forward flank. Teammate David Zaharakis was to his left calling for a handball, but O'Brien backed himself.
He saw Michael Hurley leading at him, placed the ball in front of Hurley with a neat kick, and Hurley did the rest, converting his shot and putting through Essendon's third goal of the night.
O'Brien's take on his start to his career is as balanced and measured as the athletic half-forward looked on the field.
"I was just trying to keep my emotions in check, execute when I had the ball and trust my instincts," he told AFL.com.au post-game.
"My main focus was to try get it into the forwards because they're pretty potent when they're up and going."??
O'Brien finished with 12 disposals, two marks and sent the ball inside Essendon's forward 50 on three occasions. In the Bombers' 45-point loss to the Tigers, he was a positive, a player who the Bombers see as offering hard work and a healthy dose of class. ??
Coach James Hird said this week that O'Brien would have made his debut earlier if not for a serious ankle injury that cost him 10 weeks on the sidelines.
Since returning through the VFL, O'Brien has worked at getting fitter and stronger, so that when his AFL opportunity arose, he'd be ready to take it. His nine family members nestled in the corner of Essendon's change rooms after the defeat, each with big smiles, showed he had done a good job of that.
"It was a massive step up from the VFL as I expected, but you just have to get used to it as quick as you can and play the best footy you can," O'Brien said.
"Obviously the more you play at that level the better you're going to get, but you might have to go through a few tough times first."
Callum Twomey is a reporter for the AFL website. Follow him on Twitter at @AFL_CalTwomey.
