Lewis Hamilton topped the timesheets on Day 3 of the pre-season Bahrain test as Red Bull continued to struggle.
As the season draws closer, the Milton Keynes squad’s reliability woes are persisting, and there must be serious doubt about their chances of completing a full race distance after Daniel Ricciardo only managed 28 laps before the team brought his running to a premature end to concentrate on the final day.
Pastor Maldonado completed even fewer laps in his Lotus (26), as the Renault-powered cars continue to limp their way through pre-season.
Mercedes, meanwhile, appear to have the best machine in the business right now, and Hamilton went through short runs on soft tyres that gave him a table-topping time of 1:34.265.
Despite the clear pace of the car and the comfort of having completed more miles than any other team this season, Hamilton played down his team’s performance so far.
He said: "It was nice to put together a lap, but it's difficult to know where everyone is. We won't know where we stand until we get to Melbourne."
McLaren’s bright pre-season also continued, with Jenson Button posting the second fastest time, this coming after the news of his engagement to Jessica Michibata.
Also encouraging for the Woking squad was the fact that the man from Frome completed more laps (103) than anybody else, emphasising the clear advantage the Mercedes power unit has over its Renault rival right now.
Felipe Massa completed a Mercedes engine 1-2-3 by going next fastest for Williams, although the Brazilian was two seconds down on Button’s time. Nevertheless, the Grove squad must be heartened by their performance so far.
The Ferrari-powered cars all followed with Esteban Gutierrez quickest of them all for Sauber, ahead of Sergio Perez and Kimi Raikkonen. Daniil Kvyat’s seventh place meant that Toro Rosso were fastest of the Renault-powered machines, with Maldonado and Ricciardo following.
Caterham had a more successful day than Marussia, with Marcus Ericsson completing the most laps of any Renault-engined car (98). Max Chilton could only manage four as his team spent the majority of their time in the pit lane.
Bahrain Test Day 3 results:
1. Lewis Hamilton, Mercedes, 1:34.263, 67 laps
2. Jenson Button, McLaren, 1:34.976, 103 laps
3. Felipe Massa, Williams, 1:37.066, 60 laps
4. Esteban Gutierrez, Sauber, 1:37.180, 96 laps
5. Sergio Perez, Force India, 1:37.367, 57 laps
6. Kimi Raikkonen, Ferrari, 1:37.467, 44 laps
7. Daniil Kvyat, Toro Rosso, 1:38.974, 57 laps
8. Pastor Maldonado, Lotus, 1:39.642, 26 laps
9. Daniel Ricciardo, Red Bull, 1:40.781, 28 laps
10. Marcus Ericsson, Caterham, 1:42.130, 98 laps
11. Max Chilton, Marussia, 1:46.672, 4 laps
12. Valtteri Bottas, Williams, No time, 55 laps.