Mercedes: Wolff admits his team has 'learned hard lessons'
Mercedes say they have "learned hard lessons" from their struggles for consistent competitiveness this season.
Mercedes driver Lewis Hamilton trails Ferrari's Sebastian Vettel by 14 points as the F1 season resumes in Belgium this weekend after its summer break.
Mercedes are expected to have an advantage over Ferrari on the fast and demanding Spa-Francorchamps circuit.
But Mercedes F1 boss Toto Wolff said: "The form book can be rewritten from one weekend to the next."
Vettel won the last race in Hungary at the end of July to bring his tally to four wins this season, equalling Hamilton, who this weekend could equal Michael Schumacher's all-time record of 68 career pole positions.
But the greater consistency shown by the German and Ferrari has meant Mercedes have been on the back foot most of the season after Vettel got off to a winning start in Australia back in March.
The Mercedes is on average the fastest car but it has proved difficult to work with, especially on circuits with predominantly slow corners. Historic Spa is the opposite - a series of fast sweepers in the Ardennes mountains.
Wolff said: "We have overcome a difficult start to testing and significantly improved a fast but tricky car; we have won six races from 11, including victories for both our drivers; we trail in one championship by 14 points, and lead the other (the constructors) by 39.
"But it hasn't been easy sailing. We have learned hard lessons, grown strong as a group and there are still many areas for us to keep improving."
Wolff said Mercedes were determined to try to win both titles but recognised it would be much harder than in their dominant period from 2014-16.
"History has shown that the fastest car usually brings you the drivers' title; and the best and most consistent driver pairing wins you the constructors'," Wolff said.
"So the priorities are clear: We must keep bringing performance to the car at every race - and keep racing without mistakes to maximise our performance potential at every track.
"From what we have seen in the first half of the season, the competitive balance will swing one way and another from circuit to circuit. Red Bull will be a threat if they can build on the performance they showed in Hungary.
"So we need to keep our heads down, stay humble regarding our strengths, diligent about our weaknesses and take the season weekend by weekend.
"On paper, people will assume that Spa should suit our car because it is a circuit where aerodynamic efficiency is extremely important. But we will be making no assumptions; we have to tick off the items on our work list and make sure we do the best job to maximise our potential points score."