The top four teams are all closely matched on the eve of the new Formula One season, says Mercedes team boss Ross Brawn.
Brawn says Mercedes, McLaren and Red Bull have all closed in on Ferrari in the last month.
He says Ferrari was dominant at the start of the testing season but at the last round of testing in Barcelona McLaren's Lewis Hamilton has set the quickest time.
The season opening grand prix is in Bahrain in two weeks time.
