Mercedes boss Toto Wolff says that a simple stopwatch failure was the reason why Nico Rosberg's five-second pit penalty in Hockenheim dragged out to over eight seconds.

Rosberg was handed a five-second time penalty for forcing Max Verstappen off the track when battling for third position.

It has always been the responsibility of the team, and not the FIA, to monitor pit time penalties, and it is usually done by the team manager with a standard handheld stopwatch.

However, on this occasion when the usual process failed, the team left a safe margin to ensure that the required time had elapsed.

"Even in an F1 team with all the high tech if you get to take out the instruments you don't usually use, like a stopwatch, they can fail," said Wolff.

"The stopwatch didn't start properly, and once we realised, we had to take it safe. And this is why it took longer than normal."

Wolff said it was not a human error: "It was a stopwatch failure. The damn thing failed, it didn't function like it should have done.

"We could have counted, one thousand one, one thousand two, one thousand three, but we relied on the stopwatch, and it let us down."

Meanwhile Rosberg said he didn't realise that there had been a delay until after the race, but he insisted that he was not annoyed by it.

“At the time it wasn’t frustrating, because I didn’t know," said the German. "It felt like I was sitting there forever.

"Now in hindsight, not that frustrating either, because there were so many things went wrong today, and that was one more small thing, which actually didn’t make a difference in the end.

"I wouldn’t have been able to get the Red Bulls anyway, because they were on the supersofts, and they lasted pretty well in that stint, so that didn’t make a difference.”


Gallery: Stopwatch failure caused Rosberg's pit delay