It was another impressive outing for Ferrari in pre-season testing as Sebastian Vettel topped the timesheets for the second day running, but Mercedes once again showed their immense reliability in Barcelona.
Four-time world champion Vettel was fastest on day one and he clocked a one minute and 22.810 seconds lap to once again lead the way on Tuesday.
Vettel's time was almost two seconds quicker than the pole position time set in Spain last year by Nico Rosberg, and 0.715secs faster than Daniel Ricciardo of Red Bull, who had the second fastest time.
The session ended when Vettel's car came to a halt at Turn Three, but it was another solid day for Ferrari.
However, constructors' champions Mercedes continued to clock up the miles.
World champion Lewis Hamilton completed 156 laps on day one, but German team-mate Rosberg bettered that by adding 172 on Tuesday during his first outing in the W07.
In total eight teams completed 100 laps, including McLaren's Fernando Alonso who managed more in one day than he did during the whole of a miserable 2015 pre-season.