Toyota captured the drivers' and the manufacturers' title back in 2014, but lagged well behind Audi and Porsche last year, with each of its two cars only making the podium once.

As such, the Japanese manufacturer has opted for big changes with its new-for-2016 TS050 prototype - and di Grassi believes Toyota should now again be capable at fighting at the front.

"I expect them to make a big step, because they have changed the engine and the hybrid system," the Brazilian told Motorsport.com.

"They are a good team, they won the championship in 2014. They will be strong.

"Of course, I would like to see Audi winning everything. But ideally it will be a competitive fight between all the manufacturers. It's better for everyone."

New Audi a complete overhaul

After 2015 ended Audi's five-year Le Mans 24 Hours winning streak, the German marque decided to make significant alterations to its cars for 2016, among them a switch from a flywheel system to a lithium-ion batteries.

"When you leave the rules free, people tend to gravitate towards the best solution," di Grassi said.

"At the moment that’s the lithium-ion batteries. Flywheels and super-capacitors are just not as good, and there is no point promoting a technology that is not as good.

"The car is brand new, everything is completely redesigned, re-thought, re-engineered to improve on what we had last season.

"Audi has done a fantastic job, and I’m very proud to be part of the team. They have put a lot of resources and effort in to achieve such a big step forward."

Di Grassi's sentiments were echoed by teammate Marcel Fassler, who told Motorsport.com: "There is nothing carried over from the old car.

"The hybrid system is 6MJ [instead of last year's 4MJ] and it's really good.

"We’ve also found some more engine performance and the whole package is looking really good. But now it needs to prove that on the race track.”

Interview by Jamie Klein