Seven-time world champion Lewis Hamilton is at the wheel of an significantly updated Mercedes as testing for the new Formula One season resumes in Bahrain on Thursday.
The Bahrain International Circuit will host testing over the next three days before holding the first race of the season, the Bahrain Grand Prix, on March 20.
There is growing excitement about the new season, which features brand new cars the series hopes will create better overtaking, closer racing and a more evenly matched competitive order.
At the opening three days of testing at Spain's Circuit de Catalunya in February Ferrari and McLaren both made encouraging starts and there is hope the two famous teams will be able to compete with Mercedes and Red Bull for wins from the get-go this year.
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The next three days of testing will provide the best evidence of which team is likely to be the one to beat at the start of the season, as teams turn their attention more towards outright performance.
Teams will also carry out what are known as qualifying and race simulation runs, where they will try to replicate the competitive sessions of a race weekend. These runs will help paint a picture of what the competitive order will look like for the opening race.
With brand new cars, F1 insiders expect this season to feature a frantic development race, meaning the team quickest at the Bahrain Grand Prix will not be a lock-in championship favourite.
Haas has already confirmed it will miss at least the morning of Thursday's test after it encountered a freight delay earlier this week. The cargo plane which was supposed to travel to the UK and then take its freight to Bahrain was delayed in Istanbul when it encountered technical issues on Monday.
Pietro Fittipaldi will be at the wheel on Thursday if Haas is able to get its car built in time on Thursday.
Haas finished the first test significantly down on mileage compared to most of the other teams so it will be vital the American team avoids any further delays once its car is ready to hit the track.
Seven-time world champion Hamilton will kick things off for Mercedes before new teammate George Russell takes over in the afternoon.