O’Brien was doused in Gatorade during an Adelaide club song that marked a 138-point rout of ailing Brisbane at Adelaide Oval.
“It was an awesome feeling to come off with a win in my first game,” said 201cm O’Brien, also crediting the on-field voice of Rory Sloane, Matt and Brad Crouch for his impressive introduction.
“You see a 40,000 crowd but to run out in front of one is awesome.”
O’Brien, 20, banged home a goal on debut, 16 touches and 29 hit-outs in a stellar promotion from understudy with Jacobs sidelined for a first game in four years.
“He helped me all year and ever since I got the club he has been my mentor along with Doc Clarke,” said O’Brien, backing the guidance of Jacobs and ruck master Matthew Clarke.
“Sauce was huge all week telling me how to prepare, was clear on my role for the team.
“I feel like I have been playing really good footy in the SANFL and biding my time and for the coaches to show me opportunity is awesome.”
O’Brien missed a first term shot for goal but atoned with a debut major during time on in the third term to the delight of team-mates.
“I missed out on that but I was lucky to get one in the end when Charlie Cameron let one go and I marked it. The boys were great getting around me,” said O’Brien.
Queenslander Archie Smith was a familiar foe with Victorian O’Brien encountering the exciting ruckman in the under-18 nationals
“Archie has a huge leap on him, I think we may have a few more duels to come,” he said.