2013 F1 crown was 'never on' for Mercedes - team boss Toto Wolff

For much of the first half of the season, Mercedes had the outright fastest car in F1, with Nico Rosberg and Lewis Hamilton regularly dominating qualifying.

Although race pace was harder to sustain, the duo still took three grand prix wins between them.

But asked by AUTOSPORT if he honestly felt the championship was ever a realistic goal, Wolff replied: "No, never. The championship was never on for us.

"We were just not sustainable enough with the results.

"We had peaks that were very good - we had a peak in Monaco because we just managed the weekend very well.

"Monaco was also a very good race for the team, [with] Nico - it was his race - managing the pace up front.

"And if Lewis had not made the mistake and managed the gap behind the safety car then we would have ended up in P1 and P2.

"The same actually applies for Silverstone and the Hungaroring.

"These were exceptional races from the boys, Lewis would have won Silverstone if he had not stopped and the Hungaroring was Lewis's race."

Wolff admitted that on other weekends Mercedes failed to make the most of its chances.

But he said that was acceptable at this stage in the team's development, four years into the project that began when Mercedes took over the Brawn team at the end of 2009.

"We got things right on these [winning] weekends but we never seemed to get it right on every weekend," Wolff said.

"This is OK. It is constant progress now for the team and it is the way it should be."