Ferrari's power surge has stumped their F1 rivals with the Scuderia's engine upgrade worth around a third of a second - reckoned to be the equivalent of two years of development work.

After qualifying for the German GP, in which Sebastian Vettel secured pole position over Mercedes' Valtteri Bottas, Silver Arrows boss Toto Wolff revealed the team calculated they had lost half a second along Hockenheim's straights to the Ferrari.

"If we want to stay in this championship, we have had a severe warning today," said Wolff. "They have a great power unit. We were looking good in all types of corners but we are not able to match their straight-line performance."

Wolff added: "We need to find out how we can improve our power output.

"It is a worry. If others are capable of achieving that we ought to be able to achieve that."

The Italian perspective on Ferrari's year of promise

For the first time in F1 hybrid's era, Ferrari rather than Mercedes currently possess F1's strongest engine - an upgrade which has powered the Scuderia to the top of both championships and propelled customers Sauber and Haas up the field.

"There is a lot of head scratching going on. Ferrari have found something awesome," 2016 F1 world champion Nico Rosberg told Sky F1 during coverage of qualifying for the German GP.

Ferrari's unique twin-battery system was investigated around the Monaco GP weekend before cleared by the FIA, the sport's governing body.

But it's the size and speed which Ferrari has powered up since Monte Carlo, culminating in their first win at Silverstone in a decade, which has wrong-footed their rivals.

"People are telling me that this is the equivalent of two years development on the power unit, they've found something magical," Sky F1 pundit Martin Brundle revealed. "And now I'm hearing it's not actually part of the battery or electrical system at all, it's something else they've found.

"Other teams don't know what it's about, therefore they can't replicate it, but all the Ferrari power units seem to be going very well. Ferrari have stolen the march somewhere in the amount of power they deliver at the racetrack.

"It's worth around a third of a second a lap, which in a Formula 1 car goes an awful long way."

Speaking before qualifying, Wolff also admitted the world champions had been caught by surprise by Ferrari's surge.

"They brought a step up after Monaco," said Wolff. "From Canada onwards it's been a tremendous increase in power for qualifying and the start of the race. Credit to them because it's a big game changer.

"If we knew we would do the same. Our brains are spinning to try to understand.

"The largest power we see is acceleration out of corners. It's not at the end of the straights but particularly in mid-speed corners. This is where they have done a good job."

Red Bull boss Christian Horner added: "They are doing a great job. Their engine is now the benchmark."

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