Renault has confirmed reports that it has made progress with its Formula 1 engine ahead of the 2018 season.

Late last year, the French marque encountered reliability problems and a shortage of parts.

However, customers Red Bull and McLaren have suggested progress has been made over the winter.

"Last year, we could not exhaust the engine's potential because of fears about reliability," Renault boss Cyril Abiteboul told Auto Motor und Sport.

"But now we can."

Works Renault driver Nico Hulkenberg is also confident, after his bright yellow and black 2018 car was launched.

"The top three teams will continue to be at the front," he said. "Then I hope it is us and McLaren and it will be interesting to see what Force India can do again.

"If we manage to cut the gap to the top teams in half then we will have done a good job."

Abiteboul also said he is not worried that Renault may be making a strategic mistake by having teams as strong as Red Bull and McLaren as customers.

"We cannot run away from these teams if we want to be world champions," he insisted.

"We can also learn from our customers: Red Bull in aerodynamics and organisation, and McLaren on the mechanical side."

Hulkenberg said that the challenge of Red Bull and McLaren's impressive driver lineups - including stars Max Verstappen and Fernando Alonso - must also be embraced.

"We are not bad ourselves," he added. "I don't think we have to hide from them."

On the topic of Alonso, Hulkenberg - the 2015 Le Mans winner - said that he wishes the Spaniard well for his Toyota adventure this year.

"It's not just the extra races, Fernando has to test and also be in the factories - both Toyota and McLaren. It will be quite a nice burden for him but I didn't want to do it that extremely myself," said the German.

Renault finished the 2017 constructors' championship in sixth place with 57 points.