Mercedes appear on the back foot heading into the 2021 Formula 1 season after a difficult three days of pre-season testing. 

While Red Bull looked mighty with Max Verstappen rounded out the test fastest of all, Mercedes endured a sub-optimal three days of running around the Bahrain International Circuit, leaving the reigning world champion outfit with plenty of work to do.

Both Lewis Hamilton and Valtteri Bottas struggled with the behaviour of the team’s updated W12 car and reported handling and stability issues with its “quite snappy and unforgiving” rear-end, while Mercedes was also hampered by several niggling reliability issues. 

Hamilton suffered two spins on consecutive days and Bottas also found it hard going keeping his car pointing in the right direction with a number of wide moments in the skittish-looking W12. 

Things got off to a bad start on the opening morning, when after just a single lap, a gearshift issue was detected, resulting in Bottas losing three hours of running. 

Mercedes did recover and make up for its lost track time as the test progressed, but it heads into the opening round in worse shape than 12 months ago and has more questions than answers amid an apparent resurgence from Red Bull. 

We consider the contrasting fortunes of F1’s leading two teams in our latest video - which you can watch below - as we round up our conclusions from winter testing in Bahrain…

Will F1 finally get to see that elusive two-team title fight this year? Let us know your thoughts in the comments below.