"The Renault deal is all done," he said. "Alonso staying is super news."
However, Ecclestone is not sure McLaren's switch from struggling Honda power to customer Renault engines will be a silver bullet for the once-great British team.
"I can't see why McLaren will be any happier with Renault than they are with Honda," he said.
"It wasn't Honda's fault things didn't work out, it was McLaren's. Every day they had a fight about everything, instead of working with them, which was a little bit stupid."