Nico Rosberg says he's been battling the levels of grip with his Mercedes and sees Ferrari as a real threat to his race-winning streak having topped the Friday's free practice times.
The current F1 world championship leader comes into the Spanish Grand Prix with a seven race victory run and despite topping the timesheet with a best time of 1m 23.922s he anticipates a tough battle to maintain his winning momentum at the same circuit where he claimed his first win in 2015.
Rosberg says he was continually wrestling with his sliding Mercedes and due to the much warmer conditions compared to winter testing the set-up markers pinpointed in pre-season became variable around the circuit.
With Mercedes rarely showing its full hand and turning the power up until qualifying its advantage over the chasing pack is difficult to predict but Rosberg anticipates his team has another tough fight with Ferrari.
“It was all OK today with good practice for the qualifying, for the race and everything,” Rosberg said. “The car is looking good, Ferrari seems to be very close, I think Kimi was only 0.2s away or something so we definitely need to make sure we get everything out of it. Lewis as well was quick, he just ended up with traffic so the lap time is not relevant, but I'm optimistic.
“It has been difficult because in winter testing we do thousands of laps here but it's 20C on the tarmac and now it's 40C on the tarmac and it's just a different world. The car is different, its handling, much more difficult to drive, lots to adapt.
“It's just because I remember this track from the winter so I had some expectations coming here. In the winter it just feels awesome, it's cold, there's so much grip. You come here now and it's hot, the car is just sliding everywhere, you have less grip and it just doesn't feel good but it's surely the same for everybody.”