Kimi Antonelli recovered from a loose seat and an early trip to the pits to finish second in FP2 at the United States Grand Prix, just 0.042s behind Charles Leclerc. The championship leader says the Austin weekend is a "step forward" for Mercedes' recent upgrade package.

After setting the fifth-quickest time in FP1, during the second session, Antonelli just missed out on finishing first. The young Italian finished just 0.084s behind Charles Leclerc.

Antonelli's seat forced an early stop in FP2

The problem showed up almost as soon as FP2 began. Antonelli said that his seat is 'moving around like crazy', a distraction that required an early stop in the pits.

The repair cost him real track time. It cost around 10 minutes for Mercedes to get Antonelli's seat fixed.

The championship leader said: "It was a bit of a difficult start [to FP2] because the seat was not fixed properly, so it kind of felt like being on a rollercoaster on Lap 1, with the seat moving in the high speed [corners]. We lost a little bit of time but it was still a good recovery."

Antonelli calls Mercedes' progress with the upgrade a step forward

The lap time mattered beyond Friday's timesheet. In Austin both Mercedes cars are running the latest package again, and the team is still trying to get the most out of it.

"I felt better in the car compared to FP1. There is still lots of work to do, but it was a good step forward and now we'll try to improve even further.

"Since Singapore, having that week away, we were able to analyse the data and understand better what this package needs. We're still trying to find how to put the car in the right window, but we've been taking steps forward and we'll see what we can do to improve even more."

Photo: Race Pictures

Mercedes' Trackside Engineering Director, Andrew Shovlin, also commented on the change between the two sessions. He said the team were struggling with locking, which was a big limitation in both our single-lap work and the long runs in FP1.

Russell's FP2 lap was ruined by a snap in the Esses

George Russell's afternoon was much less tidy. The Briton set only the seventh-quickest time in FP2, but finished 0.744s behind Leclerc. The Briton never got a clean lap in. His first soft tyre effort scratched for exceeding track limits and his second ruined by a huge snap through the fastest portion of COTA's Esses.

What Antonelli needs to win the title in Austin

Antonelli arrived in Austin holding a 102-point advantage over Russell. Lewis Hamilton is third, 111 points behind.

• Antonelli wins the race
• Russell finishes ninth or lower
• Hamilton finishes fifth or lower