Mercedes GP expectations were too high at the beginning of the season says motorsport boss Norbert Haug.

Haug: You could argue that our anticipation from the beginning was not exactly spot on and we had this cooling issue we had to concentrate on resolving, so once the train had started and you need to run behind the train, then it's quite difficult to catch up. But in a way, if we were in the same position it would be worrying if the gap became bigger and bigger. There is an intense rhythm of development. Speak to Ferrari, speak to McLaren, speak to Red Bull and they will admit that they have upgrades at each and every race.