Sauber on Sunday confirmed it will switch from Ferrari engines to Honda power-units next year.
The Swiss team will become the first customers for Honda, whose exclusive partnership with McLaren has resulted in a series of performance problems, since returning to Formula One in 2015.
Sauber has had a technical partnership with Ferrari since 2010.
Sauber team boss Monisha Kaltenborn defended the move to take a supply of arguably the least-effective engines, which has been questioned by many paddock observers.
"That is very momentary, how you are summarising it," she told reporters. "That is as of now. Nobody knows what is going to be the future.
"We are absolutely confident that Honda will make improvements and sort out their issues. We are convinced that it is going to happen.
"Nobody knows what is going to be in six months and we just feel that from the overall opportunities that we have there, it strengthens or fits more into the way we want to go."
Ferrari have returned to form this year and on Saturday locked out the front row of the grid for Sunday's Russian Grand Prix with German Sebastian Vettel taking pole position and Finn Kimi Raikkonen lining up alongside him.