World champions Red Bull endured another frustrating pre-season testing session after last month's Jerez ordeal at Bahrain's Sakhir circuit on Wednesday behind Force India's Nico Hulkenberg.
Sebastian Vettel's all-conquering team missed out on the first five hours of the opening day of the second series of testing before the 2014 season begins in Melbourne on March 16.
When the German world champion finally got their RB10 out on the circuit it lasted only 14 laps, his session brought to a premature end with an unspecified breakdown.
Their experience here mirrored the nightmare test they encountered in Jerez in Spain last month when they only mustered 21 laps over four days as they struggled to get to grips with the raft of new technical regulations.
"It's been a very long two weeks for everyone back at the factory," Red Bull's race engineering co-ordinator Any Damerum told the sport's official webiste, F1.com.
But he added: "I have to say that while it might not appear so on the surface there has been a big improvement since Jerez.
"We are obviously playing catch-up and for us this was very much like a first test.
"We were sidelined by a mechanical gremlin but one unrelated to the issues in Jerez. That's the way of testing.
"All these problems have to be ironed out and only reveal themselves as you progress.we're itching to get back on the track again tomorrow."
Wednesday's opening day honours were taken by Hulkenberg, the German returning to Force India after a brief spell with Sauber, posting a quickest time of 1min 36.880 after completing 78 laps.
"A very positive and satisfying day," said the pacesetter.
Ferrari's Fernando Alonso (1:37.879) came in next, one second behind, with Lewis Hamilton (1:37.908) third in the Mercedes.
Hamilton reported: "We're not aiming to be top of the timesheets at the moment, it's more about ticking the reliability boxes, but we can be happy with where we are before the halfway point of the pre-season tests."
In fourth, carrying on his impressive showing in Jerez, was McLaren's Danish rookie, Kevin Magnussen, who had the satisfaction of finishing one place ahead of Vettel (1:40.224).
The teams have three more days preparation here this week and four more next week.
Bahrain testing times
1. Nico Hulkenberg (GER/Force India) 1min 36.880sec (78 laps), 2. Fernando Alonso (ESP/Ferrari) 1:37.879 (64 laps), 3. Lewis Hamilton (GBR/Mercedes) 1:37.908 (74 laps), 4. Kevin Magnussen (DEN/McLaren) 1:38.295 (81 laps), 5. Sebastian Vettel (GER/Red Bull) 1:40.224 (14 laps), 6. Adrian Sutil (GER/Sauber) 1:40.443 (82 laps), 7. Robin Frijns (NED/Caterham) 1:42.534 (68 laps), 8. Daniil Kvyat (RUS/Toro Rosso) 1:44.346 (5 laps), 9. Romain Grosjean (FRA/Lotus) 1:44.832 (8 laps)