MotoGP world championship leader Marc Marquez sent out an ominous warning as he went fastest in the first practice session for Sunday's Aragon Grand Prix.

The two-time world champion Spaniard, who holds a comfortable 43-point lead over Valentino Rossi with just five races of the season to go, posted the best time of 1min 48.830sec in the Friday morning session at the Motorland circuit.

Rossi was second fastest, 0.186sec behind, with Spain's Maverick Vinales third.

Defending champion Jorge Lorenzo, who has won in Aragon, Spain for the past two seasons, was only fifth fastest, 0.771sec back.

The riders have three more practice sessions before qualifying on Saturday.

Source: AFP