Wolff: It's not always the fastest car that wins

Speaking ahead of the Belgian Grand Prix, Round 13 of the 2018 Formula 1 World Championship at Spa-Francorchamps, Wolff explained, "It's very difficult to make any predictions for Spa."

"If this season has taught us one thing, it's that there are no clear favourites for specific tracks anymore and that it's not always the fastest car that wins."

Hamilton has won five times, the last two races on the trot when his arch-rival Sebastian Vettel, with four wins so far this year, was expected to have the edge in his Ferrari. But the Reds have fumbled collectively and Hamilton has picked up big points for Mercedes.

Wolff pointed out, "The competitive balance seems to swing back and forth from circuit to circuit. What is clear is that our competitors are pushing extremely hard and put up a very tough fight. So we need to keep our heads down, work hard to eliminate our weaknesses and further build on our strengths, and take the season race by race."

"2018 promises to be a season that we will still be talking about in years to come and we can't wait to get out there and start racing again."

It was gruelling 'first-half' of the year, 12 races in an unprecedented spell that included a never to be repeated triple-header.

Wolff said that teams felt the load and know what to expect as the season resumes, "After five races in six weeks before the summer break, the shutdown came at just the right time. It gave us the opportunity to recharge a little and return energised for what will certainly be a hard-fought second half. Both the Drivers' and the Constructors' Championship are extremely tight and I expect it to be a close battle all the way through to Abu Dhabi."

Battle resumes in the Ardennes forest where Mercedes have won since 2015, but Wolff is braced for the challenge, "Our first stop after the summer break is Spa - an historic circuit that has been the venue of some of the most spectacular races in F1 history. Corners like Eau Rouge are known to race fans around the world and the race always attracts a huge and very enthusiastic crowd."

"From a team's perspective, the circuit is quite tricky, as it is not easy to find the right set-up for a track that has long straights, considerable changes in elevation and high-speed corners. You want to have enough downforce to be quick through the corners, but at the same time not carry too much drag for the long straights," added Wolff.

Heading to the legendary Spa-Francorchamps, Hamilton on 213 points leads the championship standings by 24 points from Vettel, while Mercedes lead the constructors' standings by 10 points.

Hamilton has won three times at the venue, with Vettel managing two triumphs at Spa.