Mercedes boss Toto Wolff wary Bottas-Hamilton battle could hand advantage to Ferrari

SHANGHAI, China -- With the opportunity of securing Mercedes' third race victory of the season on Sunday, Toto Wolff will make sure his team's "rules of engagement" are left ringing in the ears of his two drivers ahead of the Chinese Grand Prix.

Valtteri Bottas will line up ahead of Lewis Hamilton on the front row of the grid in Shanghai, with the two Ferraris just behind in third and fourth. While Mercedes appears to have the quicker car over a single lap, Ferrari's superior straight-line speed could see Sebastian Vettel and Charles Leclerc put pressure on their rivals on the kilometre-long back straight.

Wolff has always been clear that his drivers are free to race as long as it is not at the cost of the team's overall result. In 2014, a collision between then Mercedes teammates Nico Rosberg and Hamilton at the Belgian Grand Prix led to the senior management sitting down with its drivers to draft an agreement over what is and is not acceptable in wheel-to-wheel combat. The exact terms of the "rules of engagement," as they are referred to within the team, are not known but deterrents are in place to stop the drivers crossing the limit.

A version of the agreement still exists at the team even though the Bottas/Hamilton rivalry has not been as tense as Hamilton's battle with Rosberg between 2014 and 2016. Wolff said both drivers will be reminded of its contents ahead of the Chinese Grand Prix.

"I think this is a very important discussion to have and we have had that discussion since Monza 2014, that was the race after Spa," he said. "So it's part of our normal procedure."

Wolff is expecting an exciting start to the race and also highlighted the burgeoning rivalry between Ferrari's two drivers, Vettel and Leclerc, after Leclerc upset the team's hierarchy in Bahrain by outperforming his more experienced teammate.

"It's certainly, I wouldn't say explosive, but it's an interesting constellation to have the two Mercedes in front that are very much keen each of them to win -- it's about the championship -- and then behind you have the battle of the generations with the red ones and Max [Verstappen], who will be keen to recover.

"So, I think the start is going to be certainly very exciting, I hope not too much! And then if you have a decent start, it's about trying to survive these first few laps."

Bottas outqualified Hamilton for the first time this year in Shanghai and Wolff puts his improved form relative to his teammate down to the type of track.

"I think we have seen those variances between drivers even intra-team variances from race to race," Wolff said. "I think it is related to the circuit layout, driving style and tyres. The same happened at Ferrari. So I think it will be important for each driver out there to accept that you could be looking good at one track and not at the other. "

After revealing that Mercedes was losing 0.5 seconds of lap time to Ferrari on the straights in Bahrain, Wolff said the straight-line speed loss in China was slightly less and was outweighed by Mercedes' strengths in the corners.

"First of all it's important because when I read some of the stuff, it looks like a little bit of complaining that we are lacking straight-line speed. I don't mean that in any way. I think the racing car is a package of the power unit and the chassis and you need to get the job done in both of those areas.

"It is always a combination of drag and power levels. So the way I mean it is not about complaining. What we've seen on our tool is that we are losing three-and-a-half tenths on the straights but we're gaining more in the corners. So that was the difference."