After being drafted in 2008, the 21-year-old has impressed many at the Lions, with captain Jonathan Brown once claiming he had the best hands at the club.
But for a number of reasons, Cornelius has played just 10 matches in his three seasons.
This year, he played in round three and four against Melbourne and St Kilda but couldn't manage a single goal, and was banished to the reserves.
He stayed there until being recalled in round 18 against North Melbourne, where he kicked two majors.
Cornelius said while his time in the reserves was difficult, he knew there were deficiencies he had to work on.
"I didn't really deserve my turn," Cornelius admitted.
"I had to work on my defensive pressure and not being a liability when it comes to team structure. Tackling, chasing, things like that, so I had a few good weeks in ressies doing those things and when the opportunity came I was able to step up.
"I wanted to change those things. It's certainly not hard, I just had to concentrate a lot more on that stuff and the best part was that after I did those things, I was able to take some marks and kick some goals. It certainly paid off and helped me out a lot."
Cornelius said he went away and worked on his aerobic conditioning but more than anything just his defensive work - instead of dropping his head after spilling a mark, the 192cm forward said he had to switch his attention quickly to defending.
On Sunday he showed his undoubted offensive talent, taking six marks and kicking a career-high 4.2.
He said he still had a "long way to go" but was looking forward to proving himself over the remaining four rounds.
"I dreamed of kicking goals when I was a younger kid, so to do it on the big stage is exhilarating," he said.
"I knew the persistence would pay off but consistency is a thing I need as well."
Michael Whiting covers Brisbane Lions news for afl.com.au. Follow him on Twitter: @mike_whiting
