[22] The selection of tyres was criticised by teams and drivers for being too conservative and counter-productive to racing,[23] though Pirelli claimed that this was a result of the highly-specific chemical makeup of the tarmac used at circuits hosting Grands Prix.[24] After analysing data gathered in free practice on Friday, Pirelli admitted that the soft and super-soft compounds would have been better-suited to the characteristics of the circuit.Vettel completed the trifecta of fastest lap times when he topped the final session on Saturday morning, finishing two and a half tenths of a second faster than Hamilton.The positioning of his car forced race control to show yellow flags in the first sector, obliging drivers to slow down to avoid an accident.The faster lap times now meant that the softer option compound was a necessity; predictions from the teams – which would soon prove to be accurate – suggested that it would be impossible to advance to the final period of qualifying using the harder prime tyres.His team later defended the decision to have him compete in an older specification of the Mercedes F1 W03 as they felt it was better-suited to Rosberg's driving style, particularly when it came to heating his tyres.[34] The Saubers of Pérez and Kamui Kobayashi filled out the eighth row of the grid, with the team unable to explain their lack of pace despite early predictions that they could challenge Mercedes for fifth place in the World Constructors' Championship in Austin and Brazil.Jenson Button had to settle for twelfth overall when his McLaren MP4-27 lost all power late in the period, and he later admitted that he was afraid of getting caught up in what he called a "chaotic first lap".Mark Webber qualified third, ahead of Romain Grosjean, who was later demoted to ninth when he received a five-place grid penalty for an unscheduled gearbox change.[38] Michael Schumacher, who has won the United States Grand Prix on five occasions, qualified sixth in his penultimate race before his second retirement from the sport,[39] ahead of former team-mate Felipe Massa.Ferrari were later forced to defend their qualifying tactics after sending Alonso out to complete his final timed run on a set of "scrubbed" – used – tyres.