Valtteri Bottas has ended the opening week of pre-season testing on top as his time of 1:15.732 was not beaten by any of his fellow competitors during the day.
After one red flag was deployed on Thursday, Friday saw four red flags, teh first of which was caused by Sebastian Vettel who had an engine problem in the morning.
The Dane only completed four laps in the afternoon, as Haas was unable to repair the car in time to get it back out on the asphalt.
Antonio Giovinazzi was sixth and clocked the most amount of laps from a single driver during the day, circling the Barcelona circuit 152 times.
Bahrain International Circuit - Winter testing