After a dramatic start to Saturday with a heated press conference between Red Bull's Christian Horner and McLaren's Zak Brown over Formula 1's cost cap saga, the track action was intriguingly close - until Verstappen put distance between himself and his Ferrari and Mercedes rivals late on.

Verstappen, the newly-crowned double world champion, posted a 1:35.825 with his final flying lap, three and four tenths ahead of Leclerc and Ferrari team-mate Carlos Sainz.

Sergio Perez was half a second off and fourth in the other Red Bull, just ahead of Lewis Hamilton - who earlier in the session looked to be right in the mix with Verstappen and Ferrari.

Qualifying is live on Sky Sports F1 at 11pm, with build-up from 10pm.

George Russell was only seventh, although Mercedes' weekend hopes are boosted by various grid penalties in Austin, Texas.

Perez's five-place grid penalty for Sunday's race was confirmed on Friday - along with Alfa Romeo's Zhou Guanyu - while during Practice Three it was revealed that Leclerc and Fernando Alonso, who was sixth, also have drops.

Leclerc has a new Internal Combustion Engine and turbocharge, while Alonso just has a new ICE.

Leclerc will take a 10-place penalty and Alonso five.

Elsewhere in final practice, both the Aston Martins - Sebastian Vettel and Lance Stroll - surprisingly finished in the top 10, while Mick Schumacher had the one reliability gremlin of the session with gearbox issues.

The Haas driver finished 19th, only ahead of the Alfa Romeo of Zhou Guanyu.