George Russell has conceded Red Bull is in a 'league of its own' ahead of the season-opening Bahrain Grand Prix.
The defending world constructors' champions left the Bahrain pre-season test last weekend as heavy favourites having completed the three days with little to worry about and what seemed to be an abundance of speed in both long and short run simulations.
Max Verstappen topped two of the three sessions that he took charge of, finishing runner-up in the third.
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This has left Mercedes facing what is likely to be a battle with Ferrari for second in at least the first race of the year this weekend, with Aston Martin believed to be chasing in fourth.
The Brackley-based team endured ups and downs during the test, with Russell losing 90 minutes on the second day after suffering a hydraulic failure.
"It probably wasn’t the smoothest three days we could have hoped for at testing. But the learning we found is going to put us in better stead for this weekend.
"But I think it’s definitely fair to say Red Bull are in a league of their own this weekend.
"It'll probably be a nice fight for second between Ferrari and Aston Martin."
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