Victory in Texas didn't just put Kimi Antonelli on the verge of winning the Formula 1 title. It gave an important signal he could repeat the feat next year.

In recent weeks, Antonelli and Mercedes had been struggling with a package of car upgrades that often seemed more like downgrades as Max Verstappen and Red Bull took advantage to win back-to-back races.

But Antonelli’s dominant win from pole position at the Circuit of the Americas on Sunday showed he’s now confident of getting the best out of the car over a full race distance at a pace Red Bull and Ferrari largely couldn’t match.

“All this time putting so much work into bringing this new package and finally seeing the result is very pleasant,” he said.

In Singapore earlier this month, Antonelli said there was only a “very, very small” window of performance to unlock the new design's benefits before it became skittish and unpredictable.

Now the car is working as intended, he says there's more to come.

“In some places, I would say, still not as much as we expected, but in other places it is delivering very well,” Antonelli said. “We’re still struggling a little bit in low-speed with front locking, but overall, I feel like the package is finally starting to deliver.”

With much smaller regulation tweaks coming for 2027 compared with the sweeping changes implemented this year, what teams learn from late-season developments can have a direct benefit next year.

Only one of Mercedes' drivers is seeing the benefit. George Russell was at a loss for his “rubbish” pace as he finished eighth in Texas. A five-second penalty didn't help, but Russell told Sky Sports he was clueless about the rest of the yawning gap to Antonelli.

“Hopefully there are some answers somewhere but at the moment I don’t have them,” he said.

Russell has less experience with the upgrades after the team put him back on the old package in Singapore to make a side-by-side comparison.

Verstappen's still a threat after Red Bull developments made his set up more predictable, but the car is slow off the line at the start of the race and it's costing him. Verstappen started second alongside Antonelli but spent his first lap under attack from Charles Leclerc as Antonelli zoomed off into a lead that was never seriously under threat.

“The start definitely is something we’ve improved massively,” Antonelli said. “We were nowhere at the beginning of the season, and now we’re good, so that’s definitely one less thing to worry about.”