Sauber: Early points shows F1 critics were talking 'nonsense'

The Swiss outfit failed to score a point for the first time in its 22-season history in 2014, but topped the times on one day of the first test in Jerez and finished second on the other three.

That led to claims Sauber was simply chasing headline times, rather than demonstrating true performance.

However, it has subsequently scored two double-points finishes in the opening four races, with Felipe Nasr an impressive fifth in Australia's season opener.

Marcus Ericsson was on course to score points in the other two races, but a spin in Malaysia and a slow pitstop in Bahrain ended his hopes.

"We could see at the winter tests that we were more competitive," Kaltenborn told AUTOSPORT.

"People were attributing it to show runs that we might be doing.

"But that was complete nonsense because we are not into all that, so it's good to prove all these people wrong."

Sauber is currently fifth in the constructors' championship with 19 points, although Kaltenborn admitted it will be hard to defend that position as the season goes on.

"Of course, we could never have expected these kind of points," she said.

"We're very happy and content with where we are but we want to do more.

"It's going to get tougher, as we know there are teams which can do far more than we can.

"It's difficult for us to compete at that level but that doesn't mean we will give up.

"We have had four races on four different tracks so it shows we are competitive. We just have to keep pushing."