Mercedes team chief Toto Wolff says he is considering introducing team orders in a bid to halt Ferraris momentum in this years world championship.

In the wake of Sebastian Vettel's second win of the season in Bahrain on Sunday Wolff admitted that it may be difficult for Mercedes to continue to allow their drivers total freedom – and may ask new boy Valtteri Bottas to take the role of a ‘number two’ driver.

The Finn was asked to allow three-time champion Lewis Hamilton to pass him in Manama as he laboured in pursuit of Vettel in a scenario that may be repeated regularly, if reluctantly.

"We don't like it at all," said Wolff, mindful of the team's tradition for open ‘terms of engagement’ that allowed intense competition between Hamilton and retired 2016 world champion Nico Rosberg in the last three years.

"It's not what we have done in the last couple of years, but the situation is different now… So, it needs a proper analysis of what it means and where we are…

"We'd like to give equal opportunity at the start of the race. I think we owe it to them.

"Then you see what we did in the this race -- we made the call, we made the call twice, because we felt it was the only possibility of winning the race..."

For the first time in four years, Mercedes have lost their supreme dominance and face a serious battle to hang on to their drivers’ and constructors’ titles as a revived Ferrari have gained the initiative.

In Bahrain, Ferrari’s aggressive strategy and tactics made the champions look rattled and ponderous as Vettel followed up his win in the season-opening Australian Grand Prix to take a clear lead in the championship.

By seeking not to give either driver any advantage over the other, Mercedes were unable to respond immediately and delayed their decision-making after Ferrari's early move to make an ‘under-cut’ pit stop.

Wolff said he did not favour abandoning the team policy of giving the drivers’ equality and rejected the idea of backing the driver who took pole position, or was most advanced on the grid.

"That would be too harsh," he said.

"It would be the opposite of what we have done through the years. It's important, as we start the race, to give them equal opportunity.

"We would probably have taken a different decision if Valtteri had run at the front, with the problem on the tyres, and Lewis would have been second, but with Vettel, between them, there was nothing we could have done.

"That's why it was the perfect storm….

"It is our mind-set and our racing philosophy, until now, that we have given them both equal opportunity. Like here, if you have two cars starting on the front row – if they run second and first, you just have to let them race.

"When you have a problem on the car, as we had (with Bottas' rear tyres), then it is a situation to consider -- to swap them - but with a Ferrari in between, we couldn't. Three races into the season, you don't want to go there yet.”

Bottas' problems with his rear tyres were caused by a generator failure on the grid that meant the team could not bleed the air pressures for the race.

Vettel's win lifted him top of the drivers’ championship with 68 points ahead of Hamilton on 61 and Bottas on 38.

It triggered celebrations in Italy where confidence in Ferrari has soared, but has left Mercedes with a problem to solve just three races into the 2017 season.

Sochi stages the Russian Grand Prix on Sunday.