Nico Rosberg using 'very old' F1 engine for Abu Dhabi GP

The Mercedes drivers are out of sync on engine usage after Rosberg had to abandon his third power unit of the season when it was contaminated by a coolant system leak on its first weekend of use at the Italian GP, where the team introduced its major upgrade.

"We know it's going to be difficult because I have an extremely old engine as a result of having lost my fourth engine for the year, so I have a lot of miles on it and that's definitely costing me straightline speed," Rosberg said.

"It's going to be a difficult weekend as a result. But I just have to go quicker in the corners...

"The engine is very, very high mileage, very old, and this track is an engine track.

"Already in Brazil it was difficult but this track is the ultimate engine track so here it costs even more laptime."

Although Rosberg ended Friday practice at Yas Marina as the pacesetter, he believes Hamilton could have gone faster.

"Lewis didn't show his pace on one lap," said Rosberg.

"It's clear that he still has some in reserve. Today is not the real picture."

Hamilton agreed that his Friday time was not representative, saying he "didn't really get the best out of the tyres" after lapping two tenths of a second slower than Rosberg in the evening session.

He is also optimistic that he has a chance of ending Rosberg's run of five straight pole positions regardless of his team-mate's engine worries.

"I made some changes to the car and so far it feels relatively good," said Hamilton when asked if he felt he could interrupt Rosberg's pole streak.

"I might make some more tweaks tonight and hopefully tomorrow's going to be good."