Yuki Tsunoda has leapt into contention to secure a promotion to Red Bull's top team for 2025.
Throughout the Japanese GP weekend, the outfit's top figures hailed the improvement Sergio Perez has made so far this year.
But suddenly, with Tsunoda outpacing and out-racing Daniel Ricciardo at the junior RB squad and even scoring an unlikely point at home at Suzuka, a contract extension for Perez suddenly appears in doubt.
"It's his seat to lose," team boss Christian Horner said on Sunday.
"The driver market is picking up very early this year but we're in no hurry. Obviously there's a lot of interest in our seat but Checo has priority."
For his part, 34-year-old Mexican Perez - close to Verstappen all weekend at the daunting Suzuka circuit - insists that he's "very relaxed" about his future.
Ziggo Sport even reported on Sunday that Perez is asking for a three-year deal, which former Red Bull Robert Doornbos thinks is "laughable".
"That request is rejected by Marko," he said. "He thinks even with a two-year deal, he'll sit back and give up again."
Perez said after finishing second on Sunday: "Whatever comes next, I'm happy with what I am showing in this sport so far.
"It's clear that the driver market is moving now and I think a lot is going to happen in the next few weeks. I expect that within a month I will know what I'm doing next year."
Given that Perez - and his powerful Mexican sponsors - is not strongly linked with any other F1 teams for 2025, it certainly sounds as though he expects to be retained.
But Peter Bayer, the CEO at the RB team, hails the "constant upward trend" that diminutive Japanese Tsunoda, 23, is riding at present.
"He has grown from a teenager to an adult," he said at Suzuka. "He drives with incredible focus and is a joy to work with.
"He will be interesting for other teams and Red Bull is also keeping a close eye on what happens next with him."
Tsunoda is actually also linked with a move to Aston Martin, given his progress but also his strong backing by Red Bull's engine partner Honda - who are moving to Aston Martin for 2026.
But Dr Helmut Marko says Red Bull will not be rushing to sign any 2025 driver contracts.
"It would be unusual if we did that in April," he said. "We will not allow ourselves to be pressured. We will monitor everything closely and then we will make a decision later - probably in the summer period."
As for Tsunoda, Marko added: "He is very consistent at the moment and his mistakes are in the past. He has made it into Q3 three times in a row, and is more controlled on the radio now. He has really improved.
"But there are still a lot of races to go."
