By John Harrington

Since the drawn All-Ireland Final, the Dublin and Kerry managements will have spent every waking moment possible trying to find the marginal gains that might make a vital difference in the replay.

Personnel changes in the match-day 26 will be considered, as will a suite of tactical tweaks that might just wrong-foot the opposition.

Both managements will have learned a lot from the drawn match, but so too will each individual player and that’s arguably where the greatest gains can be made.

You often find that replays are shaped by players who didn’t quite play to their full potential in the drawn match and are highly determined to make the most of the second opportunity.

Kerry’s Stephen O’Brien is one player who certainly has more in him that he showed in the drawn game.

He worked hard throughout and scored a nice point in the first half, but he still didn’t hit the same sort of heights he’d previously reached during the campaign as a matter of course.

His fellow Kenmare Shamrocks club-man, John ‘Morgan’ O’Sullivan, knows O’Brien better than most having coached him for many years, and believes the half-forward could be much more influential in Sunday’s replay, especially if the Dublin defence prioritise trying to neutralise another Kenmare man, Kerry centre-forward Sean O’Shea, who was hugely impressive in the drawn match.

“You're always looking out for your own club-mate, and I watched the game again the day after and he did a serious amount of work 80/90 yards from goal,” O’Sullivan told GAA.ie.

“But Dublin had him well-corralled. They had a plan in place for him.

“What we would hope for the replay is that Dublin will really start concentrating on trying to stop Seanie (O'Shea) a bit more. If they do, that's going to open up avenues everywhere.

“Not that they ignored Seanie the last day, but coming into the game it was Stephen who had posed a huge threat and maybe Dublin focused a lot on him whereas Seanie was slightly under the radar coming into the match.

“That will flip the next day, but that won't bother Seanie either. That's the good thing about both of them, they're both very level-headed fellas.”

Seanie O’Shea has looked like a natural since making his senior debut for Kerry last year, but O’Brien has been more of a steady work in progress.

He’s always had raw ability, but he has refined his game in the last couple of years, especially his shooting.

“I would have seen him develop from a very young age in the club and he would have stood out for two reasons,” said O’Sullivan.

“One, because he was so small. He was tinchy small. But what also stood out from a very young age was that he had a really good football brain.

“As a young fella you could see he was always taking in what was going on around him on a football pitch. And, of course, he always had speed too. Great speed.

“He's added a lot to his game in the last couple of years, but that pace was always there. He was always lethal for a goal too.

“At club level he would always go for the jugular and the rest of the country has seen him do the same now with Kerry for the past couple of years.

“He's kicking scores for fun now with Kerry and that's an aspect of his game he has definitely worked hard on.”

O’Brien’s former Kerry team-mate, Aidan O’Mahony, also highlights the Kenmare man’s improved finishing, and believes the 28-year-old is now very much the complete wing-forward.

“That (finishing) was one thing that might have let him down a little bit but if you’re going that pace, you’re finishing mightn’t be as accurate,” said O’Mahony.

“I think it has (improved), I think he gets himself in better positions now and he takes the ball more into the scoring zones or that D there where it’s not percentage shots, he’s making himself very accurate.

“He was a nightmare to mark in training. You’d be going out for the internal games and he’d be the opposite end and you’d be thinking ‘Jesus Christ he’s on my wing now’.

“He’s a nightmare for a defender because he’d go at you time and time again.

“A couple of years ago, he had his head down and he’d be running into cul-de-sacs but now...The last day John Small did a very good job on him, John Small is very effective as well, but I think for Stephen, you might look at the video and say ‘right, if I need to get into this position here…’

“He’s one of those players that there’s always a goal chance in him. He’s no different to Con O’Callaghan, they’re guys who, when they get the ball, they’re not looking to kick the ball over the bar, they’re looking to go for goal.

“I think the next day, if the game opens up, we need to get him on ball because he is the one guy who will break a line, he’s no different to Jack McCaffrey, frightening pace, he’s very direct and he goes for goal every time.

“He sets up opportunities too. Stephen probably would have had a quiet game the last day compared to his standards. I would have said before the game he was definitely in Player of the Year territory, he still is, and a big Final is what we need.”

It’s probably no coincidence that O’Brien has matured into one of the most effective players in the Kerry team ever since his Kenmare club-mate, Sean O’Shea, joined the panel.

Quite often when O'Brien makes a defence-splitting run it's after he's been put clear by a perfectly weighted pass from O'Shea.

The two of them have an innate understanding from playing together at club-level, and John O’Sullivan believes they can be the key to unlocking the Dublin defence on Saturday.

“They work very well together, very much so," he said. "They have a natural understanding from playing together at club level. The know where each other wants the ball delivered.

“I'm not sure if it comes across, but Seanie is a massive provider for this Kerry team. All the ball goes through Seanie and he's up and down pinging passes.

“Stephen knows where Seanie is going to kick the ball, basically. He knows Seanie's game inside out so when Seanie gets the ball and turns with it, Stephen knows where to go.

“That's from playing club football for the last three or four years together.”