Rosberg raced for Williams from 2006-2010 where he claimed two podiums, but Williams says that they knew he had potential to be champion when he joined the team.
“I think it was pretty clear. You know when certain drivers come to you and whether they are champion material and he was,” she confirmed.
“For him, I think I heard on Sky he had won 23 races the highest number of races without winning a championship, but then you have drivers who win championships on less wins than you have ever heard of or could win one.
“He has done a great job and done everything he's needed to do. For him it probably feels like a long time in the making but he is a truly deserving world champion and I am so pleased for him.”
Williams also stated how much pressure lay on the German's head.
“I remember when he started his career at Williams as I was his press officer at the time and they were doing a shoot with Nelson Piquet and it was nice with Nico there. From that point on he has been absolutely charming and is a great ambassador and a great all-rounder for the sport so I think it is a really well-deserved world championship.
"I think for him being a son of a former F1 world champion, to achieve what he has and step out of someone's shadow it is not easy,” she continued.
“Any child of someone famous who has had those kinds of achievements knows it is not easy to step out of their shadow, Nico has done everything needed to prove he is a worthy individual in his own right and I think that is probably as important as winning a world championship.”
Bahrain International Circuit - Winter testing