Daniel Ricciardo ended Formula 1's young driver test at Jerez in scintillating form as the Red Bull driver (shown at left) recorded the fastest time of the week to sit on top of the time sheets.
The Australian completed 77 laps of the Spanish circuit and set the pace in a time of 1:17.418.
It was not all plain sailing for the British F3 champion, though, as his day's work was ended early when a large plume of smoke appeared from the back of his car and he stopped at the exit of the chicane, bringing the session to a halt.
Britain's Paul di Resta continued his impressive week of testing with the second quickest time for Force India. He also had his problems during his half-day of running. A spin into the gravel at the chicane early in the afternoon brought the red flags out, as did an incident 90 minutes later when his car cut out at the same point while the DTM driver was on an out-lap.
Wednesday pacesetter Gary Paffett and Mike Conway were third and fourth quickest for McLaren and Mercedes/Brawn, respectively. Both had half a day behind the wheel. Nico Hulkenberg's Williams and Bertrand Baguette's Sauber were behind them, the Belgian driver improving his best time on a number of occasions in the final hour.
Brit Oliver Turvey was an impressive third quickest in the morning running with McLaren, but was pushed down the order to seventh by the end of the day as conditions improved. Brawn's Marcus Ericsson, Renault's Lucas di Grassi and Force India's J.R. Hildebrand completed the top 10, although the American's two runs on his best sets of tires were spoiled by issues with the car's electronics.
Ferrari gave initial runs to the top-three finishers in this year's Italian F3 Championship. Mexican Pablo Sanchez, the last to venture onto the circuit, was the fastest of them in 11th place. The first out, Daniel Zampieri, was also the first to bring out the red flags as he spun into the gravel at the chicane early on.
Toro Rosso made a late decision to allow Mirko Bortolotti to drive in the morning before he handed the car over to Brendon Hartley.