If it was going to fall apart maybe it was always going to be here, now and in this way. This was a Revierderby that looked as if it might be Schalke’s worst nightmare in a season full of them. The distance between them and arch-rivals Borussia Dortmund was 42 points at kick-off, a gap that had never been as pronounced at this stage of a Bundesliga season before. This looked like a Saturday afternoon in Westfalen – where Dortmund had been yet to lose in the league this season – in which clichés about derbies and form books could be safely left at home.

And yet. A bruised team, mentally and physically, that even the legendary Huub Stevens has struggled to drag towards respectability, found a way to call the cops on Dortmund’s noisy party and to win 4-2. As the majority of Signal Iduna Park stood stunned at the final whistle, the home side had to face the fact that their title run seemed all but over. “Yes, obviously,” Dortmund’s manager Lucien Favre tersely replied when asked moments later.

And yet. Early on Sunday evening, Bayern Munich were meant to seal the deal on the short trip to struggling Nürnberg. Not only did they not do so in one of those strange, partially disengaged performances that have periodically popped up during the Niko Kovač reign, but Serge Gnabry’s neatly-pinched equaliser nearly turned out to be in vain, and would have been had the home side’s Tim Leibold not smacked the post with a stoppage-time penalty. Even after that, Kingsley Coman charged through with a chance for an even later winner, only to shoot straight at Christian Mathenia. It turns out that this really is The Bundesliga Title Race That Refuses To Die.

All of which might have left Dortmund fans – and perhaps a few players – feeling jet-lagged after a dizzying weekend in this most peculiar of seasons. There was enough of a journey on those few hours on Saturday afternoon for them, with the starting klaxon being a sensational opening goal, with Jadon Sancho impudently chipping over an advancing defence for Mario Götze to plant a powerful header into the top corner. At that point, it looked like being the walkover it had been billed as beforehand. Schalke had barely touched the ball, it felt like, with just 20% possession.

Dortmund goalkeeper Roman Bürki let in four goals. Photograph: Lukas Schulze/Bundesliga/DFL via Getty Images

But the intervention of VAR led to a Schalke penalty and a route back into the game after Breel Embolo’s shot hit an arm of Julian Weigl from no more than a few feet away. It was converted by Daniel Caliguri, who has his moments in these games, and it all started to unravel for Dortmund from there.

Referee Felix Zwayer later defended the decision as being consistent with current interpretations of the rules and while Favre was apoplectic about the award, his complaint was more against the authorities than Zwayer himself. “It’s so ridiculous,” said the coach. “The biggest scandal in football for years. Who invented this? Football is totally ridiculous.” Favre also complained that Sancho had been out of position after receiving treatment, having been struck in the face by a lighter thrown from the visiting supporters during the celebrations for Götze’s goal. That, and a banner among those same supporters asking for “Freheit für Sergej W” (freedom for Sergej W), the convicted Dortmund bus bomber, were a distasteful counterpoint to what was a fine performance, and a rare afternoon in the sun in a trying campaign. Marc Bartra, the former Dortmund defender who was hospitalised after the 2017 bus attack, later called the banner “unbearable, unacceptable and sad”.

After that equaliser, there was no doubting Schalke’s worthiness. Theirs was a performance that had barely seemed possible before and it was praised by Stevens after he had called for a compact, controlled group effort. It was surreal, with the crisis club showing the team who had led the table for so long under the meticulous Favre what discipline was all about.

Quite simply, Dortmund lost all theirs and with it, their hope of winning the title. A set-piece goal of extraordinary simplicity put them behind, with Salif Sané popping up between centre-backs Weigl and Manuel Akanji to smash home a header from Caligiuri’s corner. It was the ninth goal that Dortmund had conceded from a dead-ball situation in the Rückrunde alone.

Jadon Sancho doing Jadon Sancho things 🤯



His 14th Bundesliga assist of the season could be his best yet 👏 pic.twitter.com/yTA0mQiBlJ — Football on BT Sport (@btsportfootball) April 27, 2019

There was a 10th to come in the short passage of play around the hour mark that all but finished the game. It was hard to criticise Dortmund’s defence for the goal itself, a magnificent Caligiuri free-kick from 30 yards that curled into Roman Bürki’s top corner, but the beginning of the sequence was the start of BVB completely unravelling. The free-kick was awarded for an awful challenge by Marco Reus, studs up on to the achilles of the advancing Suat Serdar, to earn him a red card. Then, after Caligiuri made it 3-1, Marius Wolf inexplicably made an almost-identical challenge on the same player, also receiving his marching orders from Zwayer.

Another improbable was Axel Witsel pulling a goal back for the nine men, though Embolo quickly extinguished any hope of a comeback with a razor-sharp finish in exchange. The Swiss striker swished one arm across the other in the ‘all over’ motion before skidding on his knees on the sodden pitch in front of the travelling fans, and it was hard to begrudge a player who has been through a lot. His season, in many ways, is Schalke’s in microcosm, with occasional bursts of what could have been sprinkled among waves of hardship.

Schalke’s Daniel Caligiuri impressed in the victory over Dortmund. Photograph: Martin Meissner/AP

It almost was all over as well, as a Stuttgart loss in the late game with Borussia Mönchengladbach would have made Die Könisgblauen mathematically safe from the drop, and removed the lurking prospect of the final day home game with the struggling Swabians in Gelsenkirchen becoming a decisive one. It didn’t happen – Stuttgart won 1-0 – but Schalke, should (should) – be safe now with a six-point cushion (and far superior goal difference) to third bottom and the relegation play-off spot. They still want to finish with a flourish. “We have a lot of things to make up for,” said Serdar.

All we should say is that ‘should be’ doesn’t mean much in this season’s Bundesliga. With three games to go, it’s worth holding at least half a breath.

Talking points

• Dortmund’s next opponents, Werder Bremen, have seen their chances of Europe go up in smoke on the back of three straight losses. They were still raging at the perceived injustice of their Pokal semi-final defeat to Bayern as they were hammered 4-1 at Fortuna Düsseldorf, for whom Kenan Karaman scored a stupendous solo goal.

WHAT. A. GOAL! 😱



Dusseldorf striker Kenan Karaman picks up the ball well inside his own half and just does not stop!



Shades of George Weah 😎 pic.twitter.com/zSdZSnbbpb — Football on BT Sport (@btsportfootball) April 27, 2019

• Leipzig are guaranteed Champions League football after edging Freiburg 2-1, in a week that they booked their own spot in the Pokal final. Eintracht Frankfurt remain in the top four despite a goalless draw with Hertha – Gladbach’s slip was handy – though they look tired and uninspired of late ahead of their Europa League semi-final with Chelsea.