Mercedes are cast as underdogs for the first time in the hybrid era at the Bahrain Grand Prix, with Ferrari expected to enjoy the better of the conditions in the desert.
The Silver Arrows have been peerless in the past three seasons, but Sebastian Vettel has emerged as a genuine contender to Lewis Hamilton already this season, winning in Australia before bad fortune denied fans a battle between the champion pair in China.
"Ferrari are going to be very, very strong here. They always have been," Hamilton said. "It is going to be hard to keep with them, particularly in hot conditions."
Despite Hamilton's assertions, Mercedes have actually won at the Sakhir International Circuit in each of the last three years, with Ferrari's last victory coming in 2008, when the race was still run in the day time.
However, with strategy having decided the first two races, fans will hope the battles between Mercedes and Ferrari are fought on-track, with memories of Hamilton and Nico Rosberg's thrilling wheel-to-wheel scrap here in 2014 proving the circuit is conducive to good racing.
There will also be plenty of eyes on Fernando Alonso after he confirmed his plan to race in the Indy500, rather than the Monaco Grand Prix, although the Spaniard may hope just to finish after failing to see the chequered flag in 2017 thus far.
WHAT WE LEARNED FROM PRACTICE
If reliability does not come into play, things are extremely tight.
Both Kimi Raikkonen and Vettel ran into trouble on Friday. The Finn suffered from a part overheating, which kiboshed his FP1, before Vettel's car failed completely in FP2, although he was not kept off-track for long and both enjoyed favourable long-run pace to Mercedes - Raikkonen two seconds quicker than Hamilton and Valtteri Bottas in some instances.
Bottas has yet to get close to Hamilton in the Mercedes, but his long runs in FP2 on super soft tyres were consistent and a qualifying simulation left him just four hundredths off Vettel's top time, suggesting that the Silver Arrows new boy could finally deliver a championship-standard performance over the weekend.
A Hamilton hot lap was held up by a slow-moving Nico Hulkenberg at turn nine, which could see the Renault man punished ahead of the race.
Daniel Ricciardo was pessimistic coming into the weekend, but put his Red Bull third quickest in quali sims as 0.066 seconds separated the top three, with new parts reportedly fitted to the car which could help them close the gap to the leading two teams.
1. Lewis Hamilton (Mercedes) - 43 points
- Sebastian Vettel (Ferrari) - 43 points
3. Max Verstappen (Red Bull) - 25 points
4. Valtteri Bottas (Mercedes) - 23 points
5. Kimi Raikkonen (Ferrari) - 22 points
1. Mercedes - 66 points
2. Ferrari - 65 points
3. Red Bull - 37 points
4. Toro Rosso - 12 points
5. Force India - 10 points
LAST FIVE WINNERS
2016: Nico Rosberg (Mercedes)
2015: Lewis Hamilton (Mercedes)
2014: Lewis Hamilton (Mercedes)
2013: Sebastian Vettel (Red Bull)
2012: Sebastian Vettel (Red Bull)
Temperatures should nudge 100 degrees Fahrenheit in the desert on Saturday, but raceday is expected to bring cooling clouds at night time, which could play into Mercedes' hands if Ferrari's heat advantage is borne out.