Barcelona (AFP) - Australia's Daniel Ricciardo highlighted his status as a potential world champion on Wednesday when he clocked a new lap record at Montemelo in his Red Bull while former superpower McLaren suffered another breakdown.
Ricciardo, who racked up 165 laps, timed 1min 18.47sec, bettering the previous record set by Felipe Massa in a Ferrari 10 years ago.
"It was a good day today. I survived," said Ricciardo, who was scheduled to drive on Tuesday but was forced to sit out the session due to illness.
"Today's was an optimistic run plan and I didn't think we'd get that much done but we got through all of it, so that was good. I think I'll sleep well tonight."
He added: "I would have liked to get into the 17s, but we'll save that for the racing. In terms of the shape we're in, I think we're getting there, we're in a decent place."
World champion Lewis Hamilton was second fastest in 1min 18.400sec with Mercedes teammate Valtteri Bottas just behind on 1min 18.560sec.
"It's still a work in progress, but it's definitely going in the right direction. The team's working hard - both here and back at the factory - to continue to climb the upwards gradient which we're currently on," said four-time champion Hamilton.
While Red Bull and Mercedes dominated the time charts, it was another day of misery for former champions McLaren.
One day after three breakdowns suffered by Stoffel Vandoorne, it was two-time world champion Fernando Alonso's turn to be left in frustration.
The Spaniard completed only 47 laps before an oil leak forced his McLaren back to the pits where mechanics worked furiously for six hours to change the Renault engine.
Alonso managed to return to the track just moments before the end of the session.
McLaren have now completed the fewest number of laps in testing of all the teams on the grid with the new season starting in Australia at Melbourne on March 25.
Daniel Ricciardo (AUS/Red Bull-Renault) 1:18.047 (165 laps), Lewis Hamilton (GBR/Mercedes) 1:18.400 (90), Valtteri Bottas (FIN/Mercedes) 1:18.560 (82), Sebastian Vettel (GER/Ferrari) 1:19.541 (66), Brendon Hartley (NZL/Toro Rosso-Honda) 1:19.823 (119), Fernando Alonso (ESP/McLaren-Renault) 1:19.856 (57), Carlos Sainz (ESP/Renault) 1:20.042 (88), Romain Grosjean (FRA/Haas-Ferrari) 1:20.237 (78), Kimi Raikkonen (FIN/Ferrari) 1:20.242 (49), Lance Stroll (CAN/Williams-Mercedes) 1:20.349 (63), Nico Hulkenberg (GER/Renault) 1:20.758 (102), Esteban Ocon (FRA/Force India) 1:20.805 (130), Charles Leclerc (MON/Sauber-Ferrari) 1:20.919 (160), Sergey Sirotkin (RUS/Williams-Mercedes) 1:22.350 (80)