Agar was just nine years old when Steve Waugh hit a four off the last ball to score a memorable Ashes hundred in Sydney in 2003.
Although he fell an agonising two runs short of such a milestone on day two at Trent Bridge, Agar earned himself Ashes immortality all the same and turned the first Test on its head.
"To make a hundred in an Ashes Test would have been awesome," Agar said after stumps were drawn on Thursday.
"But I'm super happy."
However, Australia still couldn't claim to hold the balance of power and Agar believes his biggest contribution needs to come with the ball.
England are 15 runs in front at 2-80 in their second innings with danger men Alastair Cook (37no) and Kevin Pietersen (35no).
If star spinner Graeme Swann is given any kind of total to defend, he'll back himself against Australia's frail batting line-up.
Picked as an offspinner on a wicket that's turning and offering uneven bounce, Agar (0-29) is now desperate to strike before Swann gets his chance.
"Because I've been put in the side to take wickets I'm still very, very hungry for that first wicket," Agar said.
"I think if we can break the (current) partnership the power will definitely be in our hands.
"If we can get through them tomorrow, I think we can win this game."
Agar's 98 from 101 balls as a No.11 batsman on debut was as mind blowing as it was record breaking.
He arrived at the crease with Australia 98 runs behind and walked off with that same number next to his name.
His 163-run final-wicket stand with Phil Hughes (81no) was also a new Test record and it saved a collapsed Australian batting order from the embarrassment of being a frightening 9-117.
If anything, the heroics of Agar and Hughes covered a disaster.
On day one Australia lost their first three wickets for three runs in 18 balls.
Then, just as Hughes and Steve Smith (53) looked to have steadied the ship early on day two, a tornado hit.
Five wickets fell for nine runs in a 27-minute burst.
It's hard to imagine Australia winning the series if that kind of form continues, even if they do escape at Trent Bridge.
On a day of high drama, England felt robbed by two decision reviews - one that could have had Agar stumped on six.
Replays were deemed inconclusive and Australia totalled 280 for a 65-run first-innings lead.
The second call was particularly rough against England.
The next ball after Joe Root had been dismissed by Mitchell Starc (2-15), Jonathan Trott was given out for a contentious lbw.
Despite there being significant doubt over whether he nicked the ball first, the not-out decision by the on-field umpire was over-ruled upstairs.
It emerged the third umpire was unable to see a crucial hot-spot replay due to a television blunder.
England were reeling at 2-11 and sought an immediate explanation from the ICC.