Losing Schmidt would leave a big void - O'Driscoll
'Regret' isn't a word that is ever really associated with Brian O'Driscoll's career but not getting to play at a World Cup under Joe Schmidt is one that ranks high.
As Schmidt ponders his future, Irish rugby is braced for what would be a major loss and perhaps O'Driscoll more than most understands just how vital the Kiwi is.
A decision on whether or not Schmidt will coach Ireland at the 2019 World Cup is expected this month and should he decide to return to his native New Zealand, O'Driscoll insists that it would be a significant setback.
Schmidt's current contract runs until June 30, 2017 but the IRFU and their performance director David Nucifora have already made it clear that a fresh deal is on the table, should he opt to remain in this country.
Ireland have still never progressed any further than the quarter-final of a World Cup but as O'Driscoll reflected on his final one in 2011, a sense of what might have been sets in as he imagines Schmidt coaching the side.
"It would leave a very big void," O'Driscoll said of Schmidt's potential departure.
"He has done a terrific job in Ireland, full stop. Ireland look competitive in every single game that they play.
"Even the game against Argentina, we got ourselves back in the mix before running out of steam in the World Cup and lost to a scoreline that eventually probably flattered them.
"So Ireland, irrespective of who takes the field now, you feel as if we have a chance of winning the game and playing the All Blacks twice this year there is a different feeling to what it would have been in years gone by.
"You are always pretty hopeful under Joe Schmidt teams. I am envious that I didn't get to a World Cup under him.
"This is not to disrespect Declan Kidney or other coaches in any shape or form but Joe's level of detail on top of the team that we had in 2011 would have been a lovely match. Joe's level of detail with any team would be a pretty good match."
Despite not managing to clinch a series win in South Africa, O'Driscoll saw enough positive signs to suggest that defensively at least, Ireland are on the right path under Andy Farrell.
Ireland's line speed showed a marked improvement from the Six Nations and the fact that Farrell is now in charge of defence has freed up Schmidt to focus more on the attack.
"It's clear that he's (Farrell) brought much more width and he's bringing more line speed and a more direct approach. We're trying to push off an awful lot less and put players under pressure," he explained.
"If it's a ball player maybe you have to come off the gas a little bit. If it's someone who is less skilful, maybe it's about understanding the picture that's in front of you and then reacting.
"So I'm sure he'll bring that in but that appetite and desire to defend in that first Test was incredible.
"And that final tackle - you had Paddy Jackson coming in and finishing it off after Robbie (Henshaw) and Jared (Payne) did a brilliant job on JP Pietersen - it just showed that there is a hunger to work for one another.
"Conor Murray didn't deserve to fall off that tackle with Damien de Allende because he was so good in that game and the first Test, it seems wrong, but you stick a tackle and it's a different outcome and we're talking a series win."
In O'Driscoll's view, Murray is the best defensive scrum-half he has ever seen and coming from one rugby's greatest defenders, it is high praise indeed.
"I've never ever seen a defensive performance like Conor Murray's in that game (first Test)," he enthused.
"I don't know what his tackle count was (9), but it was the smartness of his defending and the way he plugged holes. There is definitely not a better defensive nine in world rugby, definitely not. And I don't think I've ever seen one.
"His understanding of where a player will potentially be in trouble, when to get in the line, when to get in the chip-line, how to boss people around, or when you need to plug holes and you can let someone else who is clearly struggling fill your role. He has exceptional understanding, and then brilliant technique on tackling people.
"Jack McGrath, playing 80 minutes full stop as a loosehead against South Africa is unreal. And he's excelled. You look at a Lions team and at the moment, is he the starting loosehead? Probably.
"I don't know if we've got a load of guaranteed Lions starters but I would definitely think that he is one and I would definitely think that Murray is another."