Barcelona - Sebastian Vettel said on Tuesday that he considers new Ferrari team-mate Charles Leclerc a "full rival" as the German prepares for his latest tilt at a fifth Formula One world title.
Monegasque Leclerc was the quickest driver on the second day of pre-season testing in Barcelona, clocking within 0.1 seconds of Vettel's leading time 24 hours earlier.
Vettel is heading into his fifth season with Ferrari since leaving Red Bull in 2014, having finished second to Lewis Hamilton in each of the last two years.
The 21-year-old Leclerc replaced Kimi Raikkonen at the Italian manufacturer after an impressive 10 points finishes in his rookie season with Sauber.
"Of course (Leclerc is) a full rival," said Vettel. "I think he is in the seat for a reason and I have to take it very seriously.