Nico Rosberg continued to set the pace for Mercedes in Saturday morning's third and final practice session ahead of Sunday's controversial Bahrain Grand Prix.The 26-year-old German, who claimed his maiden victory in last weekend's Chinese Grand Prix and was fastest in Friday practice, remained the fastest man as he delivered a best lap of one minute 33.254 seconds early in an hour-long session that he dominated.This meant he comfortably topped the times by 00.10secs ahead of defending double world champion Sebastian Vettel of Red Bull after enjoying a half-second advantage at the head of the field for most of the morning.HOT AND DUSTYVettel, who had struggled with over-heating problems during the session, delivered his best lap in the final minutes and in the most favourable track conditions on another hot and dusty day at the Sakhir circuit.That lifted him up to second ahead of his Red Bull team mate Australian Mark Webber and pushed championship leader Briton Lewis Hamilton, the 2008 champion, down to fourth in his McLaren.Multiple champion Michael Schumacher, 43, was fifth fastest in the second Mercedes after struggling with severe tyre-wear problems, ahead of Briton Jenson Button, the 2009 champion, in the second McLaren.Another champion, Finn Kimi Raikkonen, who won the title in 2007 for Ferrari, was seventh for Lotus ahead of Australian Daniel Ricciardo of Toro Rosso, Frenchman Romain Grosjean in the second Lotus and two-time champion Spaniard Fernando Alonso of Ferrari.TYRE WEARAll of the teams struggled with tyre-wear problems in the heat with sand and dust blowing across the circuit - conditions that suggest a minimum three-stops strategy for Sunday afternoon's race.Pirelli motorsport director Paul Hembery said: "The teams are all suffering with degradation - on the soft tyre it's about two-tenths per lap."I think they'll qualify on the soft tyre and the vast majority will do a three-stop strategy, moving onto the medium tyre in the race."McLaren are doing a lot of work on the soft tyre to see if they can maybe take a sprint approach with the compound in the race. Let's see."Hamilton said of Rosberg and Mercedes: "It looks as if they have cracked it now with that car. It's really fast. It's at least as good as us now!"Force India also registered times in the third free practice session. The team excluded itself from the second practice session, citing safety reasons, after a number of the team members were caught in a petrol bomb incident earlier in the week. Bahrain Grand Prix: Third free practice times1 Nico Rosberg (Germany) Mercedes 1min33.254sec 2 Sebastian Vettel (Germany) Red Bull 1min33.401 3 Mark Webber (Australia) Red Bull 1min33.663 4 Lewis Hamilton (Britain) McLaren 1min33.782 5 Michael Schumacher (Germany) Mercedes 1min33.796 6 Jenson Button (Britain) McLaren 1min33.899 7 Kimi Raikkonen (Finland) Lotus 1min33.976 8 Daniel Ricciardo (Australia) Toro Rosso 1min34.197 9 Romain Grosjean (France) Lotus 1min34.401 10 Fernando Alonso (Spain) Ferrari 1min34.895 11 Pastor Maldonado (Venezuela) Williams 1min34.918 12 Jean-Eric Vergne (France) Toro Rosso 1min34.977 13 Sergio Perez (Mexico) Sauber 1min35.067 14 Kamui Kobayashi (Japan) Sauber 1min35.128 15 Paul Di Resta (Britain) Force India 1min35.336 16 Felipe Massa (Brazil) Ferrari 1min35.536 17 Bruno Senna (Brazil) Williams 1min35.623 18 Heikki Kovalainen (Finland) Caterham 1min35.694 19 Nico Hulkenberg (Germany) Force India 1min35.773 20 Vitaly Petrov (Russia) Caterham 1min36.532 21 Charles Pic (France) Marussia 1min37.267 22 Timo Glock (Germany) Marussia 1min37.654 23 Pedro de la Rosa (Spain) HRT 1min38.973 24 Narain Karthikeyan (India) HRT 1min39.221 Second free practice timesFirst free practice timesStay with Wheels24 for the Bahrain F1 Grand Prix weekend.