Pastor Maldonado topped the times for the second time this week but it was McLaren's struggles that again headlined day three in Barcelona.
After finding a solution to a faulty seal on the electrical part of the Honda power unit and enjoying their most productive day of testing so far on Friday, a new re-engineered part to replace the seal also failed keeping Jenson Button stranded for a prolonged period on Saturday.
As a result, the 2009 world champion managed just 24 laps, setting the slowest time of the day with a 1:29.151. Another fix to the fix is set to arrive and will hopefully give Fernando Alonso the chance to conduct some decent running today.
Maldonado quickest on the super-softs
As mentioned Maldonado was quickest in the Mercedes-powered Lotus; his 1:24.348 was the best time seen so far at the Circuit de Barcelona-Catalunya, beating Daniel Ricciardo's Friday best by two tenths of a second. However, it was set on the super-soft Pirelli compound and a result the time, while quick, is not as impressive as it seems.
The fact Lotus are setting more competitive lap times does suggest that they are in a much better place than they were one year ago. Having missed the first test through a lack of finance and a delayed car the then ever so troublesome Renault power unit meant they were really very under-prepared heading to the season.
This year, however, the car seems to be much more to Maldonado's liking and despite missing day one in Jerez waiting for the car to arrive, the switch to the Mercedes power unit has meant they can get on much more with improving the car rather than dealing with problems with the engine.
Max racks up the miles
One of the stars of Saturday was Toro Rosso rookie Max Verstappen, as the Dutchman compiled some impressive figures in the STR10.
His 1:24.719 was the second best time of the day, albeit also set on the super-soft tyres, and a very competitive race simulation, which for large parts was not too much slower than that of stable-mate Daniil Kvyat in the Red Bull.
Mercedes long run pace ominous
Intermittent light rain around lunchtime meant most did not go for a performance run on Saturday. That explains the 1.3-second gap between Verstappen and Lewis Hamilton who was third for Mercedes.
The world champion, still feeling a little under the weather, focussed on medium length runs - mostly on the medium compound tyres - and was consistently the fastest of those completing similar stints.
Ferrari best of the rest
Indeed his day followed much the same pattern as Sebastian Vettel as the German also concentrated on longer runs.
The new Ferrari driver did have to recover from a slightly embarrassing spin on his first lap of the day as he lost control on a damp kerb exiting turn four, but his pace was again impressive and easily second to that of Hamilton, both men also crept over the 100-lap mark.
Kvyat continues Red Bull progress
Daniil Kvyat continued Red Bull's momentum from Friday with another series of long runs on Saturday. The Russian used the soft and medium compounds as he split the 66 laps for a full race distance into two parts both with a live pit-stop in the middle.
His pace was at times quite slow compared to the Ferrari and Mercedes, but was largely consistent and on within a tenth of Vettel giving the former world champions reason to be positive.
And as for the rest...
Sauber had a bad start to the day, missing much of the morning with a gearbox problem on the C34. Once it was fixed Marcus Ericsson was able to get out and in the afternoon set a 1:26.340 on the soft compound tyres to finish fifth overall. However, the early issue did restrict the Swede to just 53 laps on the day.
Williams split the day between its drivers as Felipe Massa ran in the morning, with Valtteri Bottas taking over in the afternoon. The team that were often 'best of the rest' behind Mercedes late last year have had a quiet pre-season and that continued again as they spent much of the day completing pit-stop practice.
The constant single laps did mount up, however, and between them the Brazilian and the Finn managed 104 laps though were well down on the lap times board.
Finally Pascal Wehrlein got his second day of running back behind the wheel of the 2014 Force India, after having to replace Hamilton at Mercedes after he was too ill to drive on Thursday. Once again it was about testing the 2015 tyres and the German DTM champion got through every compound as he managed 81 laps setting the eighth best time.
But it was the high fuel pace of the Mercedes and the ongoing issues at McLaren that were the main takeaways from a tamed third day in Barcelona, the final day of the second test is today.
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