World champion Sebastian Vettel topped the time sheets in both Friday practice sessions for the Singapore Grand Prix, easing out the McLaren of Jenson Button. But it looks like the battle for the pole and the win will be a closely fought, competitive affair. Vettel hasn’t had a pole position for five races and still has only one win on the board this year, the Red Bull struggled with qualifying in Spa and Monza, but here they look stronger. Vettel managed a time which was three tenths faster than Button, but Lewis Hamilton’s fifth place result does not tell the More…