Stress led to overdriving in 2015 F1 season, says Sauber's Ericsson

Sauber had a car that could challenge for points in the opening grands prix before it was outdeveloped by rivals, but the Swede was outscored 16 points to five by rookie team-mate Felipe Nasr across the early rounds.

Ericsson admitted his confidence was hit after a tough year at Caterham and that led to him simply trying too hard to impress his new employer.

"I came off a difficult year with Caterham where I was usually at the back and even though I don't want to admit it, it makes your confidence go down," he told Autosport.

"When you spend the whole year at the back, it's quite tough, and I think coming to Sauber was a big change and a big step up for me.

"In the beginning, every time I was on track I was keen to show what I can do and I think I overdid it.

"I pushed too hard, I was overdriving, getting a bit stressed.

"If I wasn't in front of my team-mate I was stressed about that and trying even harder next time out. It was like a snowball effect."

Ericsson said he addressed the problem around the time of the Canadian GP and began making changes to his approach.

"I sat down with the people around me sometime around Canada and we tried to look at the big picture, what is going right and what is going wrong," he said.

"We decided together that my mental approach, especially at the start of the year, wasn't the right one.

"You have three FP sessions for building up for qualifying and for the race but you don't get points for those sessions. I think that's what was wrong with my mentality in the beginning of the year.

"Every time, I wanted to show what I could do and then I changed my approach and I was focusing more on making sure I was ready for qualifying and the race and not focusing on times and performance to others.

"I focused more on myself and getting the set-up and feeling to where I wanted it. So when qualifying came, I was confident the car was where I wanted to be.

"That was the biggest change for me and suddenly I felt a lot calmer."