Grid girl controversy, Mercedes new car in action... top F1 stories of the week

Cape Town - Vettel's blistering lap, Red Bull's title contending car, grid girl controversy and more... here is your Formula 1 wrap.

Lewis Hamilton said he is not worried about the lap time put in by Ferrari's Sebastian Vettel at the final Barcelona test.

Red Bull is emerging as a potential favourite for the 2018 world championship, this came after Daniel Ricciardo smashed the Barcelona circuit record on day two of the final winter test.

Williams test driver Robert Kubica thinks modern Formula 1 cars need to trim some fat.

Also, Mercedes reveals the technical differences between its championship-winning W08 car and its W09 F1 competitor.

Formula 1 wrap:

Vettel's record pace does not worry Hamilton

Red Bull emerging as 2018 F1 title contender

Kubica thinks modern F1 cars too heavy

WATCH: New Mercedes F1 car - here's all you need to know

F1 grid girl controversy 'nonsense' - Todt