Ferrari racer Fernando Alonso says that drivers will have to be clever in 2014 in order to reach the end of races.
The Spaniard, entering his fifth season with Ferrari, believes that the sport will be very different to last year.
"The new Formula 1 rules are very different to what we were used to," he said.
"I think the concept of what constitutes a Grand Prix will actually change this year, with Saturday and Sunday being very different from one another."
"In qualifying, one will be able to get everything out of the car, pushing the new power unit to the limit, trying to get the absolutely best result," he added.
"But in the race you won’t get anywhere near that level. Last year, towards the end of the races, on new tyres, you could do very quick lap times, whereas in the closing stages this year, you will have to bear in mind how much fuel you have left, the state of the batteries and that of the tyres. You will need to be very clever to manage these parameters and the new race strategies could see drivers being unable to go flat out to the end."
Alonso also hopes that fans will not be turned away by the complexity of the new era.
"As drivers, we will get used to it quickly and so I hope these rules aren’t immediately overturned and that they stay unchanged for a few years. Otherwise the spectators could lose confident in this new Formula 1 which is very complex, even for the viewer."