Formula One: Quick guide to the season so far

Hamilton the runaway leader, Vettel back in the game

SINGAPORE: Quick guide to the 2015 Formula One season so far:

- Mercedes' Lewis Hamilton is the runaway leader on 252 points after winning seven of the 12 races so far. With seven races left, Hamilton has a lead of 53 points over team-mate Nico Rosberg, meaning he could lift the title without winning again this season.

- Four-time world champion Sebastian Vettel has convincingly restored his reputation at Ferrari after his triumphant reign at Red Bull ended with a thud in 2014. The German has 178 points to lie third in the standings, 21 points behind Rosberg and snapping at his compatriot's heels.

- With Hamilton, Rosberg and Vettel forming an established top three, the most interesting battles are in the chasing pack. Williams' Felipe Massa and Valtteri Bottas sandwich Ferrari's Kimi Raikkonen at fourth and sixth in the standings, and the Red Bulls of Daniil Kvyat and Daniel Ricciardo have also shown their capability on more than one occasion.

- Celebrated marque McLaren have disappeared from the reckoning with drivers Fernando Alonso and Jenson Button a distant 15th and 18th on the table -- an unaccustomed position for the two former world champions and one of F1's most successful teams.