So far in the 2014 Le Mans 24 Hours both the Toyota TS040 Hybrid and Porsche 919 Hybrid have demonstrated an impressive turn of speed.

Martin Sander, former director of Audi UK and now senior director of sales for Audi USA, appears quietly confident though.

"The Porsches and Toyotas are very fast. But it's rare to see that kind of pace maintained for the duration of the whole event," he says. "It's not uncommon to see some contenders start out very fast but the performance soon tails off."

Audi has previously encountered similar initially strong rivalry at Le Mans, when Peugeot campaigned its 908 HDi FAP Le Mans car.

Sander adds: "The Peugeots were quick. During one race I mentioned this to Dr Wolfgang Ullrich, head of Audi Sport. He looked at me, then just calmly responded that they could not maintain this pace. Come the next morning, they had all retired."