( CNN ) -- World champion Jenson Button fired a warning to his 2010 title rivals that he will be just as quick with new team McLaren after setting the fastest time of the pre-season testing sessions in Jerez . The British driver , who left Brawn ahead of the manufacturers ' champions takeover by Mercedes following the capture of his maiden drivers ' crown , ended the eight days at the Spanish circuit top of the timesheets on Saturday following a best effort of one minute 18.871 seconds . That run put the 30-year-old ahead of the 1:19.299 set by Red Bull 's Mark Webber on Friday and the 1:19.583 recorded by new McLaren teammate and 2008 world champion Lewis Hamilton last week . McLaren reported on their Web site that Button was `` very comfortable and confident in the car '' as he completed 108 laps in his third test with the team ahead of the final sessions in Barcelona next week . `` Both drivers will spend alternate days in the car evaluating the new bodywork and aerodynamic components ahead of the season-opener in Bahrain on March 14 , '' McLaren said . Renault 's new signing Robert Kubica was second fastest in Saturday 's sessions , completing 117 laps in long runs in the R30 . Sauber 's Kamui Kobayashi was third quickest over a similar distance ahead of Force India 's Vitantonio Liuzzi and Nico Rosberg in a Mercedes after the German took over from Michael Schumacher . Ferrari 's Fernando Alonso was sixth , while Webber was back in eighth after his RB6 could manage only 88 laps after an engine failure . Meanwhile , struggling new team Campos hope to be on the grid in Bahrain after confirming that shareholder Jose Ramon Carabante has now taken a controlling stake . The Spaniard has appointed former Force India boss Colin Kolles as team principal of an outfit which has just one confirmed driver , Bruno Senna . `` I would like to thank Bernie Ecclestone , who worked tremendously to support our efforts to keep the team viable , '' Carabante told F1 's official Web site . `` The whole rescue operation has been a race against time with the goal of always having the team run two competitive cars at the first Grand Prix of the F1 season . `` We have a lot of hard work still ahead of us but we are excited about making our F1 debut and looking forward to a competitive season . ''
World champion teammate Button set fastest time of the eight pre - season testing sessions . British driver sets timesheets at Monaco on Saturday for his new team McLaren . Teams head to Barcelona next week for final sessions before first race in Bahrain . Struggling new team are confident of competing after their new team boss .