Marc Marquez turned the tables on MotoGP championship leader Maverick Vinales by leading second practice in Austin, Texas.

Vinales lost a further place to impressive rookie Johann Zarco, who wrung a 2m 4.347s from his Monster Yamaha Tech 3 machine using soft tyres front and rear. That briefly put the Frenchman on top, until Marquez responded with a soft rear tyre of his own (combined with a hard front).

Marquez has never been beaten at COTA, while Vinales is yet to lose a race in 2017. But the new Yamaha star is unlikely to be too concerned by the FP2 results since he appeared not to try a soft tyre and had been leading prior to the late session scramble.

Team-mate Valentino Rossi again looked to struggle with front-end issues, before a late jump up the order to fourth place using the soft-soft tyre combination.

Marquez's Repsol Honda team-mate Dani Pedrosa and top Ducati rider Andrea Dovizioso completed the top six.

LCR's Cal Crutchlow, Zarco's team-mate Jonas Folger, Pramac's Scott Redding and Suzuki's Andrea Iannone completed the provisional top ten for direct Qualifying 2 places, although unlike in Argentina Saturday morning is expected to be dry.

Further back, KTM became the final manufacturer to debut a new aerodynamic fairing with a brief run on a new design by Pol Espargaro.

The fairing does not contain internal winglets, and instead appears to rely on the external shape to generate downforce... In other words it looks similar to the former winglets.

As a new entry, KTM is not restricted to only one fairing update during the season, like the other manufacturers.

There were two fallers - Loris Baz at turn one and a far bigger accident for Karel Abraham on entry to the back straight, The Aspar rider, second on the grid in Argentina, appeared to suffer possible leg injuries.

Suzuki rookie Alex Rins suffered an engine failure at the start of the session on his way to 18th.

1. Marc Marquez
2. Johann Zarco
3. Maverick Vi?ales
4. Valentino Rossi
5. Dani Pedrosa
6. Andrea Dovizioso
7. Cal Crutchlow
8. Jonas Folger
9. Scott Redding
10. Andrea Iannone
11.Jorge Lorenzo
12.Danilo Petrucci
13.Jack Miller
14.Aleix Espargaro
15. Hector Barbera
16.Alvaro Bautista
17.Tito Rabat
18. Alex Rins
19. Loris Baz
20. Pol Espargaro
21. Karel Abraham
22. Sam Lowes
23.Bradley Smith

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