Barcelona - Ferrari is looking stronger than Mercedes in testing and the Formula One championship-winning team has work to do before next month's season-opening race in Australia, Valtteri Bottas said on Thursday.
The Finn, team-mate to five-times world champion Lewis Hamilton at Mercedes, gave his assessment on the final day of the first four-day pre-season test at Barcelona's Circuit de Catalunya.
Ferrari was fastest on the first two days and the Italians also covered an impressive amount of mileage in the new SF90 car while Mercedes has been working through its programme without setting any eye-catching times.
"They do seem very strong," Bottas said of Ferrari, Mercedes' closest rivals last year.
"No matter which kind of fuel load or engine modes they are running, whatever you try to correct that for, in any case they are quick on short runs and long runs.