F1: Final test round-up shows Williams the biggest gainer

Williams finished the final pre-season Formula 1 test of 2014 with the fastest time, as Mercedes-engined cars continued to lead the way in Bahrain, and Red Bull continued to struggle.

Felipe Massa went quickest on day three of the test, lapping within a second of Nico Rosberg's pole time for last year's Bahrain Grand Prix and edging out Rosberg's team-mate Lewis Hamilton (fastest on the final day) by two hundredths of a second.

Williams was arguably the strongest performer across the final test, racking up more miles than any other team and suffering just one reliability issue, when the FW36's Mercedes engine blew up on Valtteri Bottas in the closing stages of the final day.

Meanwhile, the works Mercedes team suffered more glitches that hampered its running at this test, leading Rosberg to say that Mercedes is still not reliable enough heading toward the first race in Melbourne. The W05 required what the team described as a "precautionary" engine change ahead of day three, before a gearbox problem cost Hamilton nearly half the final day's track time.

Red Bull's test started badly when ongoing cooling issues with the RB10 forced Daniel Ricciardo to miss most of the first day and declare the champion squad had "not been up to scratch" in pre-season.

The Australian was more optimistic after a productive second day, during which he clocked 66 laps (including 20 consecutively) and set the third- fastest time, but that proved merely a positive blip in an otherwise miserable week.

World champion Sebastian Vettel failed to complete a lap on Saturday (despite two attempts) thanks to electrical problems, before a "mechanical issue at the front of the car" pitched the German off at Turn 1 on Sunday morning. He returned to the track in the afternoon, but failed to complete a race run while lapping at reduced pace.

Sister squad Toro Rosso managed more laps, but only went slightly quicker than Ricciardo with Jean-Eric Vergne at the wheel at the end of the final day, while fellow Renault-powered team Lotus suffered a disastrous test. The squad found its running spoiled by exhaust problems and engine failures, leading technical director Nick Chester to declare the team's cars would be lucky to make the finish in Melbourne.

Ferrari finally managed to complete race runs with Fernando Alonso and Kimi Raikkonen, after falling behind with its program at the previous test. But both were significantly slower than Mercedes managed, and team principal Stefano Domenicali admitted the Scuderia has "work to do" to catch Mercedes and Williams, which outpaced Alonso on the final day.

Jenson Button expressed similar sentiments about McLaren's chances after a difficult final test for his team.

Teammate Kevin Magnussen completed 197 largely trouble-free laps, but wound up only 11th fastest overall, while Button clocked only 74 after suffering a loss of drive on day two and an engine failure on day four.

Force India also had an engine failure on the final day in Bahrain with Nico Hulkenberg driving, but the German's team-mate Sergio Perez hailed the "great step" made by the team since the second test.

The Mexican topped the times on the first two days and managed more than 100 laps on each of them, including an impressive race run on Friday.

Bar the engine problem that robbed Adrian Sutil of a full day's running on Saturday, Sauber again showed the C33 has reasonable reliability but lacks speed. Sutil was only 13th-fastest overall, and teammate Esteban Gutierrez 17th.

Marussia made decent progress with its car at the final test, managing to lap within four seconds of the ultimate pace with Max Chilton at the wheel on the final day, while Caterham clocked more laps but could not get within a second of the pace of its back-of-the-grid rival.

Originally on Autosport.com