After three years of dominating Formula One, Mercedes is suddenly being forced to adapt to intense competition. Ferrari's pace at the opening three rounds has left no margin for error and at two of those three races, the pressure from Sebastian Vettel has cost the world champions victory. With a close battle developing for both titles this year, Mercedes will see its comfort zone shrink as the season progresses and how it adapts could ultimately decide the outcome of the championship.
On Sunday in Bahrain a series of small errors led to Mercedes losing a grand prix it undoubtedly could have won. Ferrari arguably had the better pace over the 57 laps, but Mercedes had given itself the advantage of locking out the front row of the grid, which should have been enough to control the race.
In the first stint the errors were obvious and unfortunate. A faulty generator on the grid meant the team was unable to bleed the necessary pressure from Valtteri Bottas' tyres, leaving the Finn with a lack of rear grip in the opening stint of the race. Lewis Hamilton, meanwhile, made a good initial getaway but suffered wheelspin as he went through the gears, which allowed Vettel to take advantage and pass him into the first corner. By the end of the first lap it was already advantage Ferrari, with Hamilton behind Vettel while Bottas struggled for rear grip as his rear tyre pressures ballooned.
The Ferrari pit wall, to its credit, took full advantage of its strengthening hand and went aggressive with its strategy by pitting Vettel for fresh tyres on lap 10. With Bottas struggling, Vettel was dropped into a small gap in the traffic down in 12th with orders to make the most of his of his fresh tyres before Bottas made his own pit stop. Mercedes was forced to react but before it made its next move, the pit wall was thrown a potential lifeline via a Safety Car.
The break in the racing meant Bottas could take on a fresh set of super-soft tyres at the correct pressures while Hamilton would be able to adopt a different strategy by taking on the longer-lasting soft tyres. The only problem was that Hamilton could lose positions by being stacked behind Bottas in the pit box, so based on a previous experience in Monaco he tried to leave a five-second gap to Bottas as he came into the pits.
"In Monaco I didn't have a big enough gap, so I knew I needed to have a five-second gap between myself and Valtteri so I slowed down to try and increase that gap and they were telling me [over the radio] 'It's one second, 1.7s, 2.3s...' then it got up to four seconds and when it got up to 4.7s I was like 'OK, now I'm close to good' so I started to accelerate a bit more."
Daniel Ricciardo was right behind him at this stage and Hamilton was already on the limit of what is allowed under the regulations in terms of slowing unnecessarily under the Safety Car.
"Daniel looked like he was going to overtake me before the Safety Car line, which encouraged me to pick up my pace a little bit, but then Valtteri had an issue in the pit stop. I don't know how much time he lost in the pit stop, but ultimately that means my gap needed to be more than five seconds. I'm pretty sure I was close to the five seconds when I got to the Safety Car line but when I got to the pit entry line, I could see he was sat there, not moving, and I just braked down to the speed limit and didn't accelerate anymore.
"I didn't slow down anymore but I looked in my mirror and Daniel was right on my tail. I moved over and it was too late. It was just a domino effect of one thing after the other cascading, and then the slow pit stop obviously."
Team boss Toto Wolff later said a loss of power to the wheel guns was to blame for the slow stops, but it was Hamilton's decision to slow to 57km/h directly in front of Ricciardo that proved most costly. The stewards take a dim view of drivers attempting to control the pace of the cars behind them in such circumstances, and the result was a five-second penalty that would hang over Hamilton for the rest of the race.
When the Safety Car pulled in and racing resumed it was only lap 16, but in the space of those opening laps the Mercedes drivers had dropped from first and second to second and fourth. The quicker of the two drivers, Hamilton, was now hamstrung by a five-second penalty and Bottas, even with a set of tyres set to the correct pressures, was still struggling for performance. Vettel, meanwhile, was free to control the race from the front meaning Mercedes, barring any issues on the Ferrari, had lost.
Desperate times called for desperate measures and Mercedes twice asked Bottas to move over for Hamilton as the two drivers' strategies overlapped. Over the past three years Mercedes have only twice asked a driver to move over for his teammate -- once in Hungary 2014 when Hamilton refused to do so and a second time in Monaco last year when Nico Rosberg was struggling for performance in Monaco. But Bahrain was arguably different, as the second of the two calls to Bottas was in the final stint of the race and effectively told the Finn not to contest second place and settle for third -- going against the team's tradition of allowing its drivers to race.
"We don't like this at all, we haven't done this in the last year and we want to avoid it as good as we can," Wolff said after Sunday's race. "Even today we tried to avoid it as good as we can, it is just a moment of realization that if you don't react, you're going to lose the race, then you have to make that call.
"It's a call you don't like to make. I think both had to have a fair chance of winning the race and having the best result, and it's only when the moment comes that you realise that if you are not changing anything you are going to lose the race, that's the moment you have to make that unpopular call."
As it turned out, Hamilton passing Bottas did not win Mercedes the race in Bahrain, but it was the only way of keeping the pressure on Ferrari in the closing stages. The pit wall believed Vettel might get caught in backmarker traffic at the end of the race but the only way Hamilton would be able to capitalise would be if he he quickly passed Bottas. In future races, similar situations are bound to emerge and the same difficult decision will have to be made. So is this a change in the team's approach to racing?
"It was our mindset and racing philosophy until now that we have given them both equal opportunities," Wolff added. "Like today we had two cars starting on the front row, if they're on second and first you just have to let them race. When you clearly have a problem on the car like we had [on Bottas car in the first stint] that would've been a situation when we consider to swap them, but with the Ferrari in between [Bottas and Hamilton after Turn 1] we couldn't. It's a tricky one. Three races into the season you don't want to go there yet."
But when pushed if the situation would be "re-analysed" as the year progressed, Wolff added: "Yes, definitely".
Nobody within Mercedes wants to influence the race from the pit wall, but it could prove to be a powerful weapon in the battle for the title this year. It seems unlikely Ferrari would think twice about sacrificing Kimi Raikkonen's race for Vettel, and as a result Mercedes cannot rule out doing the same.