The pre-season battle for supremacy in F1 2011 is currently too close to call between reigning double world champions Red Bull Racing and Ferrari, reckons Dr. Helmut Marko, whilst McLaren-Mercedes 'has the potential to catch up' before the curtain-raising Australian Grand Prix in Melbourne at the end of the month.

The general paddock consensus following the three group tests at Valencia, Jerez and Barcelona thus far is that Red Bull again has the edge on outright pace, Ferrari's joker is its supreme consistency and McLaren has some work to do, both in terms of performance and reliability.

Lotus Renault GP is emerging as a dark horse, whilst Mercedes Grand Prix is improving following a distinctly low-key debut with its new MGP W02. Marko, however, contends that RBR and Ferrari remain the teams to beat, even if you could not put a cigarette paper in-between them at the moment.

"Red Bull and Ferrari are at eye-level," the energy drinks-backed outfit's controversial motorsport advisor told Austrian newspaper Kleine Zeitung, "and McLaren has the potential to catch up before the start of the season. Mercedes and Renault are not quite at the level of the top three."

Whilst double F1 World Champion Fernando Alonso reckons his former team Renault 'are showing they are a lot more competitive than they were last year' with the innovative R31, grand prix returnee Nick Heidfeld - who paced the way on his testing debut for the Enstone-based concern in Valencia last month - is more cautious, stressing that 'there are still some teams ahead of us, especially Red Bull'.