Daniel set the fastest ever lap of the Circuit de Barcelona-Catalunya as he worked through an impressive total of 165 laps of the Spanish Circuit on a highly productive second day of the second and final pre-season F1 test.
Daniel used Pirelli's new hypersoft compound to post a time of 1:18.047 late in a morning session that saw the team focus on medium tyre runs early on before making the switch to softer compounds. The time was good enough to beat Lewis Hamilton by over three tenths of a second, though the Mercedes driver set his quickest time on ultrasoft tyres. The champion's team-mate Valtteri Bottas took third sport, half a second down on Daniel. Like Hamilton the Finn used ultrasofts for his quickest lap.
As well as pushing past Felipe Massa's 2008 track record Ricciardo also took single driver lap count honours for the day.
"It was a good day today. I survived!" said Daniel, who was forced to sit out his scheduled session yesterday due to a mild 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!
"It was a good bunch of laps today and I got a few quick ones in there, which was nice," he added. "The hypersoft tyre helped of course but we made some changes early this morning and after some medium runs then we went to the softer tyres and the changes we made seemed to help the car so there was just a bit more confidence and the track was a good temperature today so we could start to get some real testing in. It was OK; 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."
The team's impressive reliability today was highlighted by Head of Race Engineering Guillaume Rocquelin who added: "On most days at testing you draw up your run plan, with every minute of the day accounted for, and within an hour you've torn that up and started to move things around. Today wasn't like that and we managed to get through every item on the agenda.
"We focused largely on working as if at a grand prix weekend, so we tried a variety of tyre compounds, we did long runs on high fuel and then a full race simulation, including pit stops and everything. I think the hardest part of today was for Daniel. These are fit guys, but when you're not in top form to be asked to get through the workload he did today and lap in the 1m18s is pretty impressive, so hats off to him. In all, it was a very good day for us today. We'll do the same programme with Max tomorrow and hopefully we'll maintain the level of reliability we showed today."
Fourth place in the session went to Sebastian Vettel, who sat in for the unwell Kimi Räikkönen. Vettel spent his extra half day working through long runs on the soft tyre ending his outing with fourth place and a best time of 1:19.541 that left him 1.494s off the pace. Räikkönen took over driving duties in the afternoon, adding another 49 laps to Vettel's 66 on his way to eight spot on the timesheet.
The day's fifth fastest time went to Toro Rosso's Brendon Hartley. The New Zealander posted a time of 1:19.823 on hypersoft tyres late in the day after earlier suffering a spin and a stoppage.
Elsewhere, it was another tricky day for McLaren. Good work early on for Fernando Alonso saw the Spaniard post a hypersoft time of 1:19.856 that was eventually good enough for sixth place but an oil leak then saw the team confined to the garage for most of the day. After an engine change, Alonso rejoined the action in the final 15 minutes of the session to log a total of 57 laps for the day.
Renault's Carlos Sainz was seventh quickest ahead of Haas' Romain Grosjean. Sainz posted 88 laps in the morning before handing over to Nico Hulkenberg in the afternoon, with the German adding a further 102 laps to Renault the most mileage for a team, with 190 laps covered.
Sauber new recruit Charles Leclerc also had a solid day, completing 160 laps, though the Monegasque driver brought the red flags out at the end of the session when went off track at Turn 12.