The test timesheets have been confusing so far, but Red Bull is apparently still on top of the formula one world.

Since pre-season group testing kicked off this month in Valencia and Jerez, a plethora of other teams - notably Renault, Mercedes and even Williams - have looked up to the task of taking on Red Bull, Ferrari and McLaren in 2011.

But Toro Rosso’s Franz Tost told Blick newspaper: "Red Bull was clearly the best and the strongest at Jerez."

According to Estado de S.Paulo, Williams’ Rubens Barrichello - fastest as the four-day test concluded on Sunday - agrees: "Red Bull are in front."

2010 runner-up Fernando Alonso said in the Spanish press: "On the basis that Red Bull had a half-second advantage at the end of last year, they remain the reference for everybody."

McLaren’s pace at present is unclear, after Lewis Hamilton said the MP4-26 is a step ahead of last year’s car, before Jenson Button struggled with balance and was notably slow on Sunday.

"I haven’t got a clue where we are, really," Briton Button told reporters.

But Red Bull’s Mark Webber is adamant: "In general, teams that were fast last year are still fast, us included."

Meanwhile, photographers captured an interesting innovation on the RB7 at Jerez; a much bigger than usual opening at the rear of the Red Bull’s engine cover.

Cologne’s Express newspaper said the 20-centimetre wide hole is tied up with the channelling of airflow to increase downforce.

"From what I’ve seen so far, I would say Red Bull remains the favourite," Nick Heidfeld is quoted by Auto Motor und Sport.