From the exhilarating midweek high of battering Millwall in the League Cup on their own turf to... whatever the hell that was at Port Vale. Reading were spirited, organised and inventive in South London but the polar opposite of all those qualities in a dire 1-0 defeat on Saturday.
I say "dire", but I should be more specific with that. Ruben Selles rightly pointed out after the game that the first-half performance wasn't the issue while the second-half one very much was.
Indeed, the Royals put in a first-half showing like that against Peterborough United a week earlier: a bright start, only to fade and lose ideas. Early on, Reading were bright, positive and energetic, disrupting a home side that didn't know how to deal with an aggressive press, and creating chances for the front men.
The crowning one of those chances came 12 minutes in. Marauding full-back Nesta Guinness-Walker charged into the area, was taken down and up stepped Andy Carroll to the spot... saved! While the 'keeper was off his line as the penalty was taken, Carroll should still have scored.
Reading's momentum subsided over the rest of the half, but they still had good control over the contest. The hosts were limited to some fairly low-quality chances and you felt at that point as if some half-time changes could push Reading up a few gears in the second period.
Where Reading's first two league games of the season really differ however is in what happened after the break. The Royals certainly got worse in both cases, but against Port Vale it was a real collapse, in a way that to me mirrored the first half at Rotherham United at the beginning of last season.
A comically poor winner in the 72nd minute from Ben Garrity was only part of it. Reading couldn't clear their lines and the ball looped painfully slowly over debutant 'keeper David Button for 1-0.
There may have only one goal this time, not four, but the scoreline could have been the same, such were Reading's weaknesses at the back. In this case it was a collective defensive failing rather than primarily the fault of the goalkeeper, although again one player took the lion's share of fans' stick: Tom Holmes.
He certainly had a rough afternoon, looking shaky and unsure of himself. Holmes seemed to lose his head, not helped by a barrel of booing being sent his way from the away end. While it was understandable, laying into a player whose confidence was already shot was only going to make the problem worse. It'll be a big test of his character to bounce back in his next game, whenever that is.
Down the other end, Reading had no answer to Port Vale, whether at 0-0 or 1-0. The Royals managed a healthy 62% possession, but finished with nine shots and just one on target - Carroll's penalty - to show for it. Not only are new recruits needed, both up top and out wide, but developing the in-possession side of this 4-2-2-2 system and eradicating old habits (hoofing the ball up to Carroll) will take time also.
Reading lacked fluidity and cohesion with the ball. It appeared as if, when the bright opening didn't yield a goal, the Royals didn't know how to respond. That's understandable for a side that is, in essence, still going through its pre-season preparations.
Selles tried a few substitutions to freshen things up. Besides Matty Carson replacing Guinness-Walker as a defensive sub (probably, as Port Vale had been getting joy down that side), we also saw Caylan Vickers replace Kelvin Ehibhatiomhan, Lewis Wing come on for Charlie Savage and Mamadi Camara replace Femi Azeez.
Late on, Harlee Dean also came on for Sam Hutchinson, pushing Andy Yiadom into midfield with Dean going to right-back. Reading didn’t have any other options on the bench for changing things up in the middle of the park, but it was good to see Dean get more minutes under his belt ahead of hopefully more substantial involvement to come.
None of those subs worked really. Vickers was lively up top and Wing hit the woodwork with a cross, but that was pretty much as good as it got for Reading in the second half.
At full time, cue angry jeering from the away end. Reading had been utterly naff after the break and, while chants of "you're not fit to wear the shirt" were a tad harsh, they weren't completely unfair.
Is Tuesday now a must-win? It's hard to conclude it isn't. While Reading did so well at The Den a matter of days ago, negativity from league defeats builds up quickly and must be nipped in the bud as soon as possible.
Selles has come in for some flak due to his team selection at Port Vale, going entirely for the same outfield 10 that faced Peterborough United on the opening day rather than drafting in any youngsters from the Millwall game. I can see why he probably did it, not wanting to overwork a young group when established players are available (personally I'd have brought in Nelson Abbey, Mamadi Camara and others), but changes are badly needed ahead of Cheltenham Town's visit.
Although the squad's not finished, Selles has options to make those changes. Harlee Dean, Lewis Wing, Mamadi Camara and Caylan Vickers will all be among those pushing for a spot in Tuesday's XI.