The 30-year-old had recovered enough to enter the contest as she seeks a fifth consecutive world championship title at Beijing on August 22.
Her phenomenal record has sometimes been taken for granted, but the incumbent IAAF athlete of the year knew she had to defeat some formidable opposition to sustain a legacy which sits alongside two Olympic titles and four world championships.
Schwanitz set a personal best of 20.77m in May.
Adams had not thrown beyond that mark since beating Schwanitz with a throw of 20.88m at the 2013 world championships. China's Lijiao Gong and American Michelle Carter have also surpassed 20m this season. Gong finished this morning second with a throw of 19.75m and Carter third with 19.37m.
"A lot of things were going through my mind," Adams said. "My warm-ups felt good but everything got so tense in the competition.
"I took a risk [competing here] but was willing to do so. I knew there was a high chance it [the record] would go today. All the top girls were here and had competitions under their belts. I can only work on this.
"I actually have more motivation to go back and work on something I'm good at. I really enjoyed competing but c'est la vie. At least the record will be hard to beat."
In May, Adams told the Herald she could see her Olympic dream literally slipping through the fingers of her right throwing hand.
At the lowest point, the ring digit and pinky wouldn't respond to the simplest of tasks. She couldn't pick up the phone, cut her fingernails or scratch her hair because she had no strength. It led to momentary doubts about her future as she chases an unprecedented New Zealand feat next year - the prospect of winning gold medals at three consecutive Olympic Games.
Adams said today brought a sense of relief.
"This is kind of good because I can start building the house again after a massive year with rehab and surgery. I'm not upset but disappointed because as athletes, that's what we do."
Schwanitz described the tension and thrill to beat Adams for the first time, after the pair arrived in separate vehicles but walked into the stadium within metres of each other.
"That was a crazy competition because I didn't know what Valerie could do. I'm expecting more from her in Stockholm. In the last throw I wanted to add something and it worked [Schwanitz extended her victory margin by 13cm]. I expect Valerie to be in top shape by Beijing."
