In proving that Marcelo Bielsa's ever-present optimism was far from misplaced, Leeds simultaneously gave fans reasons to share his hope and allowed it to be dashed at the death. The performance was a balm that soothed worries, a sweet tonic for recent woes, the result an acid that burned and left a bitter aftertaste. Losing to a somewhat soft stoppage time penalty was particularly sour.
The major positives were how well Leeds frustrated and stifled the European champions and the way they fought back to level in the final 10 minutes. A first Premier League goal for Joe Gelhardt, an assist for Tyler Roberts and signs of the football that made last season so much fun were important additional bonuses.
The negatives were how much of a role Leeds played in all three Chelsea goals and that they managed to undo their good work so close to the end, having worked so hard to fight back.
Had it been the walloping so many were expecting, in light of the once-again threadbare nature of the squad Bielsa took to face the Premier League title hopefuls, defeat might have been easier to take.
Instead, the what-ifs were torturous and hope assumed its traditional role as a killer.
The fact is that Leeds need to be perfect, or as near as damn it, to beat teams of this quality and for so much of the contest they achieved it. Teams of Chelsea's quality need few chances, however, and ruthlessly punish anything shy of perfection, so in making mistakes Leeds lost the game.
In terms of the table, the 3-2 defeat gave them nothing but that's not to say they came away from Stamford Bridge entirely empty handed.
Thomas Tuchel predicted intensity and a fight from the visitors that would not cease until they were in the showers, and he could not have been more correct.
The fight was necessary, though.
An injury list that appeared to be waning just in time for a nightmarish run of fixtures, had suddenly and without warning waxed again. The loss of the only-just-returned Patrick Bamford, Kalvin Phillips, Liam Cooper, Rodrigo and Pascal Struijk gave Bielsa more than enough excuses to howl at the moon in anguish and despair. Instead, he remained stoical and optimistic in the lead up to the game, believing his players could and would give themselves a chance, even with a bench that boasted just one senior player.
Tuchel had injury problems too, yet his bench featured Romelu Lukaku, Christian Pulisic and Hakim Ziyech.
It was his team who made the better start, too, making it difficult for Leeds to play out from the back and doing enough to keep the game almost exclusively in the Leeds half of the pitch early on.
Ilan Meslier was busy, initially, but not overly troubled and although Leeds could only borrow the ball from Chelsea briefly to punctuate the hosts' dominance, they were defending ruggedly and with some comfort. Stuart Dallas and Jamie Shackleton worked hard to try and equal Timo Werner and Marcos Alonso on the right and despite room for Thiago Silva to roam into down the middle, Chelsea could create little.
That bought Leeds time to build their way into the game and finally, through Raphinha and Tyler Roberts, do a little attacking of their own.
The Brazilian's deflected shot was cleared over the bar, his free-kick was palmed out by Edouard Mendy and then when Roberts played the ball into the dancing feet of Daniel James, Raphinha was handed an even better chance, from 12 yards.
Alonso's clumsy challenge was a stonewall penalty, needlessly poured over by VAR Mike Dean before the inevitable conclusion, and Raphinha punished the defender for it.
Chelsea, as expected, came roaring back after conceding but were rebuffed and Leeds tried to build again, a period of keep-ball in the home half of the pitch hinting at growing confidence. Reece James' wild lunge on Daniel James hinted at growing frustration. Roberts flying into one on Werner, going through the German to get the ball at the cost of only a throw-in, only increased the Blues' chagrin.
But their breakthrough, when it came, had as much to do with Leeds as it did Chelsea. Just seconds after Diego Llorente implored his team-mates to calm down, they gift-wrapped a goal. Meslier floated the ball in the air to Dallas who didn't seem to get a shout and failed to control in any case, allowing Alonso to take possession, link up with Werner and pass it across the area for Mason Mount to tuck home at the near post.
A tiny number of poor decisions, imperfections in the execution of the plan and Chelsea's innate attacking efficiency was all it took to leave the game level at the break.
And it happened again before the game was an hour in, a stout, solid start to the second half ending with Raphinha's risky, sliding challenge on Antonio Rudiger in the area.
Referee Chris Kavanagh initially signaled a corner but once VAR drew his attention to his monitor, there was only one likely outcome and when Jorginho stroked the ball past Meslier Bielsa's optimism became harder to share.
The fight never left Leeds, Adam Forshaw leading an endless pursuit of possession as the visitors continued to play like a team who believed, but time was slipping away.
Only nine minutes remained when Bielsa finally sent on Gelhardt for Raphinha. Seven remained when Leeds produced their best passing move of the match, unlocking space on the left for Roberts to cross and Gelhardt to steer the ball into the net. It was his first touch, the deft, first-time glancing contact of a natural finisher. It was a moment that sent the away end and his family watching on from their living room wild. It was hope. But it wasn't enough.
Leeds were walking away from a gunfight with a result when they shot themselves in the foot.
In the five added minutes Chelsea were always going to get one more chance and it was handed to them on a plate, Mateusz Klich's needless contact with Rudiger allowing him to go to ground and Jorginho to win it from the spot.
Still they fought, even after the whistle as things boiled over, proving Tuchel right. Bielsa was right too. When the burning pain of defeat fades there will still be optimism.