It was incredibly tight at the top of Friday's timesheet, however, with less than a tenth of a second covering Ricciardo, Ferrari's Kimi Raikkonen and the Williams of Felipe Massa.
Ultimately the Australian's 1m 24.574s - set on Pirelli's yellow-marked soft tyre - proved enough, with Raikkonen finishing 0.01s and Massa 0.098s down the road.
“It was good,” said Ricciardo. “We wanted to get a day with 100-plus laps on the board and we did that and more today. It was very solid. We also got through some pit stop practice and some good long runs, which is very positive.
“I know it’s just testing but it is encouraging seeing us on top or at least in that front group. Obviously you have no idea what everyone is doing, but it is encouraging. The car feels good. It has similar characteristics to RB10 in terms of how the chassis feels but that’s a good thing, as I think we had a pretty good car last year. All in all a really good day’s work.”
Commenting on his and Ferrari’s progress, Raikkonen said: ““Today was not ideal, we had some small issues which prevented us from running as much as we wanted, but still we managed to do other stuff, try things and learn. We are going in the right direction in all areas and the team did a good job over the winter.
“Of course, racing is a different story from testing, but so far it has been good. The team bosses have managed to put the right people in the right places. It’s still early days, but everybody seems to enjoy it more. For the next test we’ll try to put the right things into the car”.
Sergio Perez was fourth in the year-old Force India VJM07, fractionally ahead of Mercedes' Lewis Hamilton. The two-time world champion had not been expected to drive on day two, but took over for the afternoon session after Nico Rosberg's running was ended as a precaution so as to not aggravate a trapped nerve in his neck, which could have jeopardised his fitness for the final day on Sunday.
“My back has been a bit of an issue but I know what it was,” reported Rosberg. “My position in the car was not quite right but I've been lucky with it really and it should be fine for a full day on Sunday. I'm just being a bit cautious and decided to get out of the car at lunch today. It's a different circuit with this new car so it felt a bit different, but in general it was ok. I wasn't so happy with the car this morning but then we found our way quickly with the setup and in the end it felt pretty good.”
Hamilton set his best time on the white-marked medium tyres, but was still able to get within four-tenths of Ricciardo's overall benchmark.
Rosberg's morning left him sixth overall, also within a second of Ricciardo, while Fernando Alonso ended what was McLaren's most productive day so far in 2015 in seventh. The Spaniard racked up 59 laps in total, even though the team are still waiting for a replacement seal on the MGU-K component of Honda's new power unit.
“It’s been good to put some laps on the board - we’ve pushed through the programme today, and achieved more than we anticipated,” commented McLaren’s racing director Eric Boullier. “Our running was relatively smooth, and we’re starting to catch up with our programme.
“We’re happy with what we’re doing - we’re still not looking at outright performance as we still have a long list of systems checks to evaluate. The car is reacting as we expected, but it’s too soon to go into a race simulation, and, as a result, too soon to be sure of our overall performance.”
On his first test for Lotus, 2014 GP2 champion Jolyon Palmer wound up eighth fastest, as Sauber's Marcus Ericsson and Toro Rosso's Carlos Sainz Junior rounded out the top 10.
“Today went well,” said Palmer. “We racked up a lot of laps and I got a good feel for the car. It was very slippery first thing with the cold track, it was certainly very difficult with the hard tyres combined with the low temperatures!
“Through the day there was a good mix of conditions and set-ups to work with. There was a lot to take on board with the different settings for the car and the different programmes we were running, so it’s been a pretty steep learning curve. It’s been a very positive start for me and I hope my work has benefited the team. I loved being in the car and I can’t wait to get back out on track!”
Sainz Jr triggered the red flags shortly after midday when he went off and into the gravel at Turn 9, while Ericsson caused a separate stoppage when he came to a halt on the start-finish line half an hour from the finish.
Testing continues at Barcelona on Saturday.
Unofficial Friday testing times from Barcelona:
1. Daniel Ricciardo, Red Bull, 1m 24.574s, 143 laps
2. Kimi Raikkonen, Ferrari, 1m 24.584s, 90 laps
3. Felipe Massa, Williams, 1m 24.672s, 88 laps
4. Sergio Perez, Force India, 1m 24.702s, 121 laps
5. Lewis Hamilton, Mercedes, 1m 24.923s, 89 laps
6. Nico Rosberg, Mercedes, 1m 25.556s, 66 laps
7. Fernando Alonso, McLaren, 1m 25.961s, 59 laps
8. Jolyon Palmer, Lotus, 1m 26.280s, 77 laps
9. Marcus Ericsson, Sauber, 1m 27.334s, 113 laps
10. Carlos Sainz Jr, Toro Rosso, 1m 28.945s, 100 laps