Following a disappointing test in Bahrain last week, Red Bull are faced with a race against time to have a competitive car by the time the season starts in Australia next month.
The reigning Constructors' Champions had a disappointing time at the Sakhir circuit last week, where both Sebastian Vettel and Daniel Ricciardo struggled with reliability.
Vettel didn't leave his garage at all on the first morning of testing and only made an appearance on track 45 minutes before the session was called off.
On the second day, though, the German had a much better time of it and completed 59 laps in his RB10.
Ricciardo's time in the new Red Bull car were cut short by technical issues on days three and four, during which he only completed 28 and 15 laps respectively.
Following the test in Bahrain, the Red Bull rookie admitted that the team needed more time on track to work on ongoing technical problems if they are to challenge for a podium position in Melbourne in less than three weeks time.
"I guess we still need more time," Ricciardo admitted.
"We have four more days coming up and hopefully we can maximise those. I have to say that on the run we did today the car did feel better.
"But unfortunately another problem arose and we couldn't exploit that potential. I hope we can do more running next week.
"Obviously, I would have liked to do more this afternoon but we still have tomorrow ahead of us and it's important to be ready for that. The car is definitely making progress though. It's coming together bit by bit.
"We'd love a big chunk all at once but that's not the way it works, so we have to be patient.
"But it is coming and we're heading in the right direction."
Red Bull have one more opportunity to test the car's reliability and Ricciardo is pleased that he gets a first crack at the Bahrain track when the third and final test starts on Thursday.
"I'm happy I'm doing the first two days," Ricciardo added.
"At this stage we just need laps and I'm just looking forward to get back in the car."
Red Bull race engineer Andy Damerum revealed that the Milton Keynes team will have an updated car at the third pre-season test.
"We've made some very good progress, particular on day two, but we've also had a number of problems that have again held us back," Damerum admitted.
"The engineering team will head back to Milton Keynes now to plan the next moves and we can only look forward and try to get everything in place for the next test."