F1 testing: Sauber denies doing glory runs at Jerez

Felipe Nasr put Sauber on top on day three of the test, while its drivers were second behind Ferrari on every other day.

On each occasion the Sauber time came on soft tyres, but Ericsson's Wednesday best was set early in an 11-lap run, indicating a heavier fuel load.

Asked by AUTOSPORT how much of its hand Sauber was showing this week, Ericsson replied: "We have quite a bit of margin, to be honest, so that's positive.

"We've had a really good test. It's been very positive that every day we've done a lot of laps and we've had no real issues with the car.

"And it was interesting for me driving on day one and day four to see the progress we've already started to make.

"The car I drove on Sunday to the car I drove this afternoon is quite a few steps on in feeling."

Sauber failed to score a point for the first time in its F1 history in 2014, but Ericsson said the vices apparent in last year's C33 - which he tested in Abu Dhabi during the winter - appeared to have been cured.

"It's difficult to say because I'm coming from a Caterham an this is quite a big step up," he said.

"But also compared to the car I tested in Abu Dhabi, we have improved.

"I think the car has made progress. It's a better car this year.

"It's more stable in general, and under braking and through the corners it gives the driver more confidence.

"Also I think Ferrari have made a good step on the power unit compared to the one I drove in Abu Dhabi. But still we have to wait and see what others have got."

The Swede added that the Jerez pace had been good for Sauber's motivation after its tough 2014 season.

"I got the feeling all winter that everyone in the team is really excited about this season," Ericsson said.

"I think this week made that feeling even better and gave more energy to the guys back home."