Earlier in Japan, it seemed a rescue deal between F1's energy drink camp and Ferrari over a supply of 'A spec' engines was now very close.
"The racing should be on the track, not in advance," Ferrari team boss Maurizio Arrivabene told the Italian newspaper Corriere della Sera.
"We, like Mercedes, sell cars and engines, so we can speak with anyone without problems. Then it is obvious that for a deal it is a matter of supply and demand," he added.
Not only that, Gerhard Berger – famously close to Red Bull owner Dietrich Mateschitz – hinted that Mercedes may also be back in the fray.
But by Sunday, the situation has clearly changed.
"After careful analysis, we took a clear position," Mercedes' Toto Wolff declared. "We do not want to do it (supply Red Bull).
"Red Bull is a good brand for formula one but first of all we have to think about ourselves," he insisted.
Mercedes has decided instead to align with the backmarker Manor, which would open up a race seat for 2016 for its reserve and DTM driver Pascal Wehrlein.
"It could well be that it will work out like that," said Wolff, "but first of all some pieces need to fall into place. And to a certain extent we are on hold because of the situation with Lotus."
Indeed, struggling Lotus has a Mercedes engine contract in place for 2016, but the Enstone team could either collapse or be bought out by Renault.
The final option for Red Bull is therefore Ferrari, but Germany's Sport Bild reports that the Maranello team is shying away from offering an 'A spec'.
Red Bull, however, says it would rather quit F1 than run a 'B' engine.
"Our position is different to that of Ferrari, McLaren or Williams," said Christian Horner.
"For us, the sport must be worthwhile from a marketing perspective, and to ensure that, we must not be limited in terms of having access to the best tools," the Red Bull chief added.
And so the specter of Red Bull and Toro Rosso's withdrawal looms, and the very real possibility of F1 filling the gaps on the grid with three-car teams returns.
Auto Motor und Sport said the small teams like Force India wouldn't mind, with official Otmar Szafnauer suggesting it may result in the team being paid "25 million more" to cover the costs.
Mercedes also sees a bright side.
"There are many good young drivers on the market," said Wolff. "You could put them in competitive cars and have a strong field of 24 cars.
"But the priority must be to keep Red Bull on the grid."