Formula One champion Red Bull could be racing against themselves in Bahrain this weekend judging by pre-season testing, according to Mercedes' rival George Russell.
Red Bull's double world champion Max Verstappen and Mexican teammate Sergio Perez have been sounding confident after their new car was quickest at the Sakhir circuit last week.
Some commentators have suggested the pair could potentially be at least half a second a lap faster than their closest rivals, with Verstappen saying the car was better than last year's in every area.
"I think it's definitely fair to say Red Bull are in a bit of a league of their own this weekend here in Bahrain," Russell told reporters.
"But I think it would probably be a nice fight for second place, probably between Ferrari and Aston Martin," added the Briton.
Aston Martin were seventh overall last season but their new Mercedes-powered car has looked quick and reliable, putting in impressive long runs in testing with double world champion Fernando Alonso at the wheel.
Russell, who claimed Mercedes' only win last season, said testing was a good indication of form but teams would have a better picture of where things stood after qualifying on Saturday.
"It's important to remember we all try and design a car that's fastest across the 23 race season and Bahrain is definitely a bit of an outlier," he added.
"So, I don't think the picture of this weekend will be the full picture for the whole season."
Russell said Mercedes had shown last year they could accelerate development and overcome problems, such as the bouncing that tormented them early on.
"I think even the improvements we're going to probably bring to the car this weekend compared to the test will take us a step closer," he said, while emphasising that Bahrain had unique characteristics as a circuit.
"I'll be surprised if the gaps are that large at other circuits," added the Briton, whose team won eight constructors' championships in a row until Red Bull did the double last season.
"The good thing is there's not too many races at the start of the season so it gives us some time to develop in the wind tunnel and back at the factory to fight for when the main block of races come."
