World champion Sebastian Vettel failed to complete a lap on another disastrous day of pre-season testing for Red Bull in Bahrain.
It has been a forgettable time for the Milton Keynes-based marque, who enjoyed their most productive day on Friday when Vettel's team-mate Daniel Ricciardo clocked up 66 laps, with his best a one minute 35.743 seconds.
But they now find themselves back to square one after Vettel broke down twice; with the German first stopping halfway round his out lap and then three hours later he only just made it out of the pit lane at the second attempt after lunch.
The RB10 then made no further reappearance and with reliability over speed set to be the key component for scoring points during the early part of the season, Red Bull would appear to have serious concerns ahead of the curtain-raiser in Australia in a fortnight.
"At the moment we obviously have lots of different problems we are curing," Vettel said.
"It's not the best situation to be in but we can't change it. Everybody is extremely motivated to fix it, but it doesn't happen overnight.
"We can just hope for a better day tomorrow and then to have a decent start to the season in Melbourne, but at this stage obviously reliability is still a big question mark."
Felipe Massa set the fastest lap with a time of 1min 33.258secs and managed to complete 99 laps in his Williams, which left the Brazilian in a confident mood.
"We had a very good day doing almost 100 laps. We did a lot more performance work in the car, which is something that we haven't done so much of so far. I'm really happy with the car and feel we found a good balance," he said.
It may be Mercedes who will come away with the most satisfaction, however, with Williams sporting their power unit and Nico Rosberg clocking the second fastest time and 103 laps for the Brackley-based marque.
The 28-year-old clocked a fastest time of 1:33.484 but chalking up over 100 laps despite losing most of the morning due to an engine change will give Mercedes plenty of confidence ahead of the new season.
"That was an incredible effort by the team and I'm really happy with our day's work," Rosberg said.
Kimi Raikkonen completed his pre-season testing on Saturday with 87 laps in his Ferrari, who had a problem relating to a connector which meant mechanics had to partially dismantle the car in order to get it back up and running.
"I'd hoped to do more laps, but this wasn't an easy day," Raikkonen said. "We lost some time this morning when we had to fix something on the car, but then we managed to make up for some of it in the afternoon."
Kevin Magnussen and Nico Hulkenberg clocked up 88 and 115 laps in their Mercedes and Force India cars respectively, while Caterham had a day to savour after Marcus Ericsson managed 117 laps of the track.
Romain Grosjean could only manage 33 laps in his Lotus, with Adrian Sutil only managing a solitary one in his Sauber.
"This is why we are testing. Of course I would like to drive as much as possible, but you have to look at the overall picture and the team decided to focus on and get ready for the final day of testing tomorrow," Sutil said.