O'Brien was used as a substitute in Saturday night's seven-point win at the Gabba, but after the second-quarter injury to ruckman Trent West, was thrust into the action sooner than expected.

 

After a nervous beginning, the 23-year-old thrived, finishing with 15 disposals and the all-important go-ahead goal late in the fourth quarter.

 

O'Brien plied his trade in the Essendon VFL team and was given a lifeline by the Lions in last year's rookie draft.

 

Following his elevation to the senior list this week, he intends on doing everything possible to keep his position.

 

"My goal is to play every game for the rest of the season and hopefully win as many games as we can," O’Brien told AFL.com.au outside a buzzing Lions' dressing-room after the win.

 

"If you have to work harder for it … I think it's sweeter.

 

"I'm 23 now and played 10 games in the NEAFL and got my confidence there and came into the game today thinking I could play my role, and I think I've done that."

 

O'Brien shot into the spotlight with six minutes remaining after winning a free kick around 60m from goal.

 

He was then the beneficiary of a 50m penalty after Jarrad Waite shoved Tom Rockliff over off the ball.

 

The resulting goal gave the Lions their first lead since early in the third quarter. They did not relinquish it.

 

"I actually thought it was a free kick against me," O'Brien said.

 

"I gave a bit of a fend off that I thought was a bit high on (Bryce) Gibbs, but he must have got me high too, so the umpire gave it to me.

 

"I think Rocky got a whack and I got the 50m and thought, 'I'll be able to kick this now'. It was great - great to come from behind and get the win.

 

"To come up here (seniors) and to play OK and for the team to win, you couldn't ask for a better start to an AFL career."