THINGS we learned (but already sort of knew) in Croke Park on Saturday night.
Eoghan O'Gara is the most impacting of impact players.
Kevin McManamon knows how to finish a goal.
If Michael Darragh Macauley ever gets injured or generally loses his way, Dublin are in dire trouble in midfield.
If Stephen Cluxton ever gets injured or loses his way, Dublin are twice as goosed.
Rory O'Carroll brings a sensibility to the Dublin full-back line you only really notice when he hasn't been there for a while.
Kevin McLoughlin is a great bit of stuff. As is Cillian O'Connor.
So substantial is the faith which courses through this Dublin football team, no situation – no matter how seemingly bleak – is unsalvageable.
Mayo, for all their excellence as a team, will never shed the doubt that cloaks them until such time as Sam Maguire is finally liberated.
And if form holds and both do win through to September after inevitably annexing their respective provinces again, we're in for one hell of an All-Ireland final.
Other than that, the only thing left to observe about Saturday's 3-14 to 2-17 draw is that, for entertainment, it was as good as the league gets.
To recap, Dublin were five points down with five minutes to play, having lost their goalkeeper, captain and arguably most influential player, Stephen Cluxton, to a straight red card in the first half.
Yet Mayo were sickened by a couple of excellent goals from O'Gara and, had Jack McCaffrey pointed an effort even further into injury-time, they would have travelled west treating deep, deep scars.
So afterwards, when Jim Gavin described his players as "a remarkable group of men," it would have been hard to argue the toss with him were you so inclined.
"They've got great character," he gushed, "they display it to us all the time, great commitment and resolve never to quit, that esprit des corps that was in them last year certainly hasn't gone away."
James Horan, meanwhile, was understandably less enthused.
"To concede that much with a couple of minutes to go is very disappointing," he said.
"We had been conceding a lot of goals all the league campaign and three more today, so yeah, that's disappointing."
The key passage of the drama arrived with only injury time to play and Mayo three points ahead.
Horan's men attempted to 'ice' the clock after O'Gara put some doubt in their minds with a smart finish from Jason Whelan's pass before a couple of points at the other end seemingly sealed it.
But Séamus O'Shea was dispossessed by Diarmuid Connolly ... not as involved as centrally as those who marveled at his All-Ireland club final performance would have hoped, but this intervention was utterly crucial.
As an aside, any random glance at Connolly when he wasn't on the ball would have confirmed that, mostly, he spent his evening being physically dogged, verbally goaded and generally obstructed by just about every opposition player to happen into his orbit.
Anyway, he laid on to Alan Brogan who put a delicious pass over to O'Gara who rocketed a shot into the top of Rob Hennelly's net for a draw which could yet have both medicinal qualities for this Dublin team and positive consequences for a semi-final spot.
"To be down to 14 men for the large portion of the game and still create those opportunities, from a coaching perspective it's very satisfying," Gavin admitted, while Horan vented his frustrations with referee Cormac Reilly. "We thought the referee's display as well today was pretty poor, to put it quite mildly, unbelievable at times," he contended.
Reilly's biggest contribution was sending Cluxton off and, in that, his call was right. And if Mayo were justifiably aggrieved at the consistency of application with regard to some frees, they were also repeatedly guilty of 'screening' Dublin players' off-the-ball runs without rebuke.
Certainly, Horan was peeved at his team's failure to see out the game, despite having the benefit of an extra player for over 45 minutes and having destroyed Dublin at midfield.
In McLoughlin, he had the game's most influential player (1-3 from play and 1-2 in assists) and, by the 26th minute, Dublin had also lost Paul Flynn to a suspected concussion.
And with 15 minutes to go, Mayo were six points up and seemingly safe.
In O'Gara – named to start but sprung from reserve – Dublin had a match-saver, though Jonny Cooper was probably their most consistently productive player over the course of the game.
And given the high number of summer starters in Gavin's team, it bodes well for them that they salvaged something more tangible than pride.
"It's a great test for the Dublin squad now to refocus and get themselves right for next weekend (when they go to Omagh)," Gavin observed.
"If we've two more games, fantastic. We'll be guaranteed one anyway. Either way, the guys will have competitive games with 10 weeks to go to Championship."