Valerie Adams has produced the best throw of the year to win the Diamond League anniversary event in London this morning (NZT) - acknowledging a perfect tune-up for her world title defence in two weeks.

With the best athletes in the world returning to the scene of last year's Olympic Games, Adams also said the performance brings closure on the site where Belarusian Nadzeya Ostapchuk cheated her out of what should have been one of the most prized moments of Adams' career.

In what is her 38th victory on the bounce, Adams' 20.90m is the best effort in the world this year and another step closer to her personal best of 21.24m.

"I'm pretty happy with that. I had great consistency throughout the whole competition. It was awesome," Adams told Fairfax Media from London.

"I'm especially pleased with the progression I've made over the last few weeks. In training, Jean-Pierre [coach] and I are heading where we need to go. I'm happy, he's happy, it's all good.

"To be that close to the 21-metre mark is always the goal and it's very encouraging.

"I've also been able to close a chapter that has been hanging around a little bit. It's nice to be able to think about London and this stadium, both of which I love, and have a positive memory.

"At the moment athletics is in the limelight for the wrong reasons again and it's great to revisit here and come away with celebrations.

"The stadium was packed and Londoners really made it a great environment."

Adams' consistent series of 20.71m, 20.79m, 20.82m, 20.31m, 20.90m and 20.40m is emphatic proof the New Zealander is the one to beat for the year's biggest prize in Moscow next month.

German Christina Schwanitz was way off the pace, over a metre back, in second place with 19.74m and American Michelle Carter third with 19.24m.

Double Olympic champion and three-time world champion Adams now looks to add to her glittering CV, hoping to win a fourth straight world title in Moscow next month.