5 Dec, 14:49
The Ireland Under-19 squad to face Australia Schools at Ravenhill on Saturday week (December 14) has been announced.
The game marked O'Callaghan's eighth appearance in Lions red and his first taste of game-time since a short cameo as a replacement in Munster's final fixture of the season against the Ospreys on May 15.
Having made two Test appearances against New Zealand on the 2005 tour, the big Corkman is eager to nail down a place in the Lions side to face South Africa on June 20.
Saturday's performance was the first step on the way to that and O'Callaghan, sporting a black eye after a hard-fought victory over the Cheetahs, was pleased with how it went.
"It was good to get a run-out. I got the jersey in the hotel and you get a little bit emotional...it's the pinnacle of your career," he said.
"The last Lions tour I was into it from the Argentina game and once you start playing games you're on tour.
"It was tough (training away and not being involved in the first two games), it really was.
"Ever since the Leinster game it's been my sole focus and main goal and that's no disrespect to the Munster games we had but this was always in the back of my head.
"It was great to get a game under my belt, it was a difficult game and pretty physical all-round."
Having gone 20-0 up, the Lions looked poised to pile on the points in their second game against Super 14 opposition.
But the Cheetahs turned the game into a real arm wrestle and O'Callaghan admitted as much afterwards, highlighting the Lions' struggles at the breakdown and the work there of abrasive Cheetahs flanker Heinrich Brussouw.
"You're 20 points up and you need the next score, whether it's three or five, score next.
"You get three or four scores ahead of these teams and they lose a bit of hope, but they scored next and then made a bit of a game of it.
"When we did play to our pattern, I thought we played them off their feet a bit.
"But their six (Brussouw) was very good, to be fair to him. What he did was he'd make a tackle and he'd get back on his feet and get on the ball early.
"People might think there were a few close calls, was he on his knees and so forth but that's a new rule: first man in has all the rights so that's something we're going to have to get better at.
"The game we're trying to play, everybody has to be able to arrive at working height at the breakdown and make an impact.
"When it comes to that it doesn't matter what number you have on your back. The pack is going to have to put their hands up there and we need a bit more work-rate in getting to those."
O'Callaghan, a natural number two lineout jumper, also expressed his satisfaction with the changes in law that have restored the influence of the two jumper in the set piece.
"Two is back. I'll be honest, I said it all along about that ELV that for a two jumper it was a balls.
"You just weren't getting any ball because their hooker was allowed to come in. It just didn't make any sense. So, I'm glad that rule was changed."