The Brit made the phone call before this year’s German Grand Prix to request a meeting over a drive for 2019.
It worked, with Russell being announced as one of the team’s drivers for next year’s campaign.
“My first contact with them was about two weeks before the Hockenheim race,” Russell told Autosport.
“I had a phone call with Paddy and I told him, ‘I want to be in Formula 1 next season and I want to be in a Williams, can we have a meeting with yourself and Claire, and discuss the matter further?’
“That was the real point I knew things were moving in Formula 1 and I needed to get in there before I missed an opportunity.
“It was probably the Hockenheim weekend [that was] the first indication or point of contact with Williams and things started progressing from there.”
Russell worked with Lowe for a brief time whilst the latter was still at Mercedes, before he made the move to join the Williams team.
The young Brit has been supported by the Mercedes team since 2017, and has tested for them several times.
Mercedes boss Toto Wolff has said in the past that the team would not pay for its juniors to find seats in F1, which could be one of the reasons that Esteban Ocon might be out of a seat.
Russell said that he felt comfortable with making the phone call, and that Wolff’s words made him more proactive in the situation.
“I always feel it is better coming from the horse’s mouth, rather than the likes of Toto or whoever from Mercedes making that point of contact for me,” the 2017 GP3 Champion continued.
“As I knew Paddy from when he was at Mercedes we had a bit of a relationship, so I was more than comfortable picking up the phone with him and arranging to meet himself and Claire.”
Mercedes had already told Russell that he would get an opportunity at motorsport’s top table if he produced good results.
Good would be an understatement, with the Brit on the brink of securing the F2 Championship, with six wins and four poles this year.
“When you’re in the negotiation period coming off the back of bad weekends it’s difficult to sell yourself,” Russell added.
“When you’re come off the back of a race win, as the saying goes, ‘you’re only as good as your last race’.
“If you’re winning the race in pivotal moments it helps a huge amount.”