This season's Premier League has been an unpredictable rollercoaster, and Manchester United have been far from exempt in the uncertainty. Making definitive predictions about what will happen between now and the end of the season is thus inherently risky.
However, it looks as though United's recent improvement—which was once again on show against Chelsea—will be too little, too late to fire them into the Champions League places.
Diego Costa's late equaliser felt incredibly significant to Louis van Gaal's side's season. In absolute terms, it meant the gap between the Red Devils in fifth place and Manchester City in fourth is six points rather than four. It also arrested a two-game winning streak which had looked set to run a while longer.
However, it also belied a frailty in United's makeup which will surely rear its head again before the end of the campaign.
And Van Gaal can hardly afford another slip between now and the end of the season if he wants to get his side back in the Champions League.
In order to even get into fourth place—a finish which would have been considered below par at the start of the season when an improvement on last year was the target—United will have to overtake one of Manchester City, Arsenal, Tottenham Hotspur or Leicester City.
The cushion those sides currently have is six, seven, seven and 12 points respectively.
Before Sunday's game, Van Gaal said, per the Guardian: "I have the feeling [that we are back in the title race] if we can beat Chelsea."
That was before the weekend's other results, though, which brought wins for three of the top four clubs. The only team not to win was Manchester City, defeated by the most surprising February league leaders in Premier League history—Leicester.
By the time their game rolled around, even if United had beaten Chelsea, they would have been 11 points behind Leicester with 39 points left up for grabs in the 13 games remaining. Overhauling all four teams ahead of them in those 13 games would be a huge ask for a team in the form of its life, let alone a United side who again showed their vulnerability.
In spite of that vulnerability, there had been tangible improvements in their play in the two games prior to the Chelsea match—and many of those continued at Stamford Bridge.
Van Gaal had called the side's attacking performance against Stoke "sparkling," per the Guardian, and applied the term to the display at Stamford Bridge in his spiky post-match interview, per the Mirror.
And there was plenty of truth to that. In the first 25 minutes of the game, United were dominant. They had 65.9 per cent of the possession, but unlike so much of this season, they turned that into chances—they had six shots to Chelsea's one, with three hitting the target in that spell.
Chelsea grew into the game in the latter stages of the first half—between the 25- and 45-minute marks, they had 52.2 per cent of the possession and took five shots to United's two, though only one of those was on target for the home side.
In the second half, though, Van Gaal's men came out firing, getting four of six shots between the beginning of the half and Jesse Lingard's 61st-minute goal. Chelsea had two shots in that spell, neither on target. The game looked to be United's for the taking.
The structure of the United team looked as effective and well balanced as it has done for several months. Juan Mata and Wayne Rooney formed the central fulcrum of the attack, with Anthony Martial and Lingard providing pace and incision on either flank.
The full-backs—both playing in their natural positions—provided ample width, and it was Cameron Borthwick-Jackson's fine cross which eventually led to United's breakthrough.
Following the goal, though, the flaws that look likely to deny United success this season became clear. Chelsea totally dominated the rest of the game as the Red Devils retreated into their shells.
The home side had 68.2 per cent of the possession after they went behind, with eight shots to United's four, and four shots on target to United's one.
David De Gea was called upon to provide heroic interventions, which he duly provided, but Van Gaal's substitutions did not help his side's cause. The arrival of Morgan Schneiderlin in Fellaini's place seemed a sensible move, but he was unable to get much of a foothold in the game.
The removal of Lingard for Memphis Depay, though, bore the bitterest fruit. It was the Dutchman's sloppy pass—with Mata and Rooney waiting in the box—that conceded possession for Chelsea's equaliser.
The twin failings of an inability to make their dominance count for more than one goal when they were on top and an inability to exert themselves on the game once they had gone ahead were hardly unique to this game.
The attack has obviously been a problem all season—albeit there have been significant improvements in both output and style of late. However, the failure in game management once they had gone a goal up brought to mind similar incidents earlier in the campaign.
United survived their Champions League home tie with Wolfsburg, but it relied on a backs-to-the-wall effort once they had gone ahead. Against Bournemouth, the Red Devils played by far their best football once they had gone behind and appeared to retreat within themselves after they equalised.
The recent 3-3 draw with Newcastle United was another example of their inability to protect a lead.
So while the attacking improvements have indeed been "sparkling," the balance of attack and defence still doesn't look quite right, and there is a fragility to United's confidence which makes the chances of a sustained run of form seem slim.
And a sustained run of form is likely to be needed if they are to overhaul the points gap to the teams above them. That, or they will need to rely on some sort of implosion from one or more of those teams.
There is some possibility of that, though it does not seem particularly likely. Manchester City are seeing out the season with a manager who is being replaced in the summer. Perhaps they will thus allow their intensity to slip, particularly if they get cut further adrift of the title race.
However, with Pep Guardiola set to arrive, the City players will want to ensure he has Champions League football in his first season, and that they impress him as he pays attention from a distance.
Arsenal have been phenomenally consistent in achieving top-four finishes. Tottenham Hotspur may have a history of missing out, but their form is excellent and barring a missing back-up striker, their squad looks well equipped.
Leicester—well, the Foxes are in the middle of one of the most remarkable moments in the history of the sport, and predicting how long they can ride the wave seems futile. It was supposed to have crashed long before now.
Van Gaal can perhaps derive certain positives from the fixture list. The Red Devils play each of the teams currently above them between now and the end of the campaign. Favourable results in those games will narrow the gaps.
There are also plenty of games between the current top-four, which could benefit United if the right teams drop points.
If United's attack had clicked a month or two earlier, it could have been very different. Van Gaal, though, took a long time to happen upon a winning formula—in spite of how obvious it has seemed from the outside that he should deploy Mata at No. 10 with quick players on the flanks.
It may be that Costa's goal for Chelsea is just a footnote and United do manage to sustain a run of form which leads them back into the Champions League. It may be that one of the teams in the top four collapses between now and the end of the season allowing an inconsistent United back into the race.
For now, though, that goal feels very significant. The post-Stoke City optimism has already dissipated and Champions League qualification looks a long way off.
It will take what looks like a pretty unlikely set of circumstances for United to make it.
All advanced statistics per WhoScored.com.