Christian Horner predicts Formula One is in for a thriller this season as the "same culprits" battle it out at the front.
Last season Sebastian Vettel came from behind to win his third Drivers' Championship title by three points over Fernando Alonso.
The duo, though, were by no means in a race of their own as Kimi Raikkonen, Lewis Hamilton and Jenson Button all played their part as did Mark Webber.
This season, Horner is predicting more of the same from the usual suspects.
"We've got all the same culprits, some of them in different teams. But it's got all the hallmarks of a really competitive year," said the Red Bull team boss.
"I think that 2012 was a great year for F1, and I think 2013 has got all those same ingredients, so it could be extremely tight.
"It's so difficult to tell. Their cars will be updated again through the testing before Melbourne, but you can see all the teams have carried over their experiences from their previous cars, so it will only be when we get to Melbourne that we'll know where we really are."
Where the teams were - at a surface glance - after the first day of pre-season testing was McLaren's Jenson Button was on top with Webber second. The Red Bull racer was 0.848s off the pace and completed 73 laps on Tuesday.
"Today is a really a data gathering exercise, but everything is running reasonably to plan," said Horner. "We're getting a lot of good data. It's good to be blowing off the winter cobwebs.
"The goal this week is to learn a bit more about the car, to complete as many laps as we can ideally. It's a get to know you process. We're working to a programme and just ticking a lot of boxes at the moment.
"We have a limited amount of testing, 12 days. It's important for us to use each one as constructively as we can.
"It's very few days when you consider that is only six days for each driver - six days of preparation is not much before they go into their first Grand Prix. If imagine a tennis player only playing six matches before going into a Grand Slam. It's unique to F1.
"But these guys train very hard, we split the testing between the two drivers, and they'll be ready by the time we get to Melbourne."
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