Vettel managed just 11 laps with the RB10 over his two days, and now hands over to teammate Daniel Ricciardo.
"Our current problems are not with the team, but in the engine area. The team has more than excellent know-how." - Dietrich Mateschitz.
Something is going on with the Red Bull power plant.
"We're confident we'll run a bit smoother." - Daniel Ricciardo
After Red Bull's catastrophic opening test at Jerez last week, even F1 backmarkers Marussia and Caterham are currently ahead of the formerly-dominant world champions' game.
Rob White is deputy managing director (technical) of the Renault Sport F1.
Nancy Knapp Schilke, F1 correspondent