Dublin's Barney Rock scores what proved to be the winning goal in extra time back in 1987. Photo: Connolly Collection / Sportsfile
In recent years, Dublin have shifted their free-taking duties around. Stephen Cluxton and Bernard Brogan took care of the bulk of them but Diarmuid Connolly was also on duty from placed balls in their ill-fated 2014 All-Ireland semi-final with Donegal. That day, a few kickable frees went awry and Gavin moved to solve the problem.
Ahead of the 2015 season, Gavin relieved Brogan and Co of that pressure when he handed Rock the frees. And with that responsibility came a place in the team.
Rock's ability to deliver from placed balls was never in doubt. Gavin knew the Ballymun man well from his days with the Dublin U-21s but a combination of injury, club duty and an uber-competitive forward line meant his chances with Dublin had been limited.
His chance with Dublin brought pressure but there has always been pressure. Being Barney Rock's son and a free-taker couldn't have helped a young man trying to feel his way into the most competitive set-up in football.
"That pressure comes with being Barney's son," former Dublin player Ray Cosgrove agreed.
Rock Snr, of course, is regarded as a legend in the capital, a status earned from his exploits during the 1980s - helping Kevin Heffernan's so-called '12 Apostles' overcome Galway in the infamous 1983 All-Ireland SFC final in which he scored a brilliant first-half goal.
Barney also enjoyed a famous win over Mayo in the 1985 All-Ireland semi-final, a clash that went to a replay which Dublin won well. And while Kerry won the final, the Dubs' chief marksman ended the year by collecting his third All-Star.
Rock Jnr has a habit of doing things in reverse order. He played for Leinster as a 19-year-old long before he lined out for the Dubs. And he appeared in the Championship for Dublin before starting a League match. In fact, he didn't start in the League until the first round last year. And that was the first day he started and finished a game for the Dublin seniors in League or Championship.
By the time last year's All-Ireland final rolled around, Rock was the only Dublin player to start every game across the O'Byrne Cup, League and Championship. But his accuracy from frees had fallen away in the closing stages of the Championship and at the short whistle in the final, he was called ashore.
He had tackled hard and kicked a pair of frees but that wasn't enough to hold on to a spot in the Dublin forward line. Gavin threw on Kevin McManamon and Rock was left to watch the rest of the final from the bench. Dublin won but on a personal level, the biggest day hadn't gone well for Rock. He would need to find more to stay in the Dublin team.
Fast forward to this year's semi-final win over Kerry and Rock is at the centre of the conversation again. Only this time for very different reasons.
Rock kicked 0-12, including 10 placed balls, to bring his return for the Championship to an incredible 93pc.
But for Cosgrove, it was his contribution from play that impressed him most.
"This year I'd seen a change in his physique," said the Kilmacud Crokes man. "I think if you look over the last couple of years his speed off the mark probably was letting him down, but I think his physical conditioning this year, he's bulked up and he's more powerful.
"The first ball that he won he was out behind Aidan O'Mahony, as a forward I'd be watching the movement of the fellas inside. Aidan played as a sweeper and Dean just came out in front of him, won the ball and it's something that you wouldn't have associated with Dean over the last couple of years.
"I believe that was the best performance I've seen from Dean in a blue jersey. Not just the frees that he kicked and the accuracy from his free-taking, his use of the ball when he was coming out.
"His tackling when he was coming out with 10 minutes to go; that was an aspect of his game that I would have questioned and that was probably a reason that he wouldn't have been a constant in the team; his work-rate and his ability to win dirty ball.
"If he repeats that performance now the next day he'll be handful for any Mayo defender."