The London Olympic champion Rudisha clocked seasons best time in the world 1:45.01 to defeat Australia's top 800m man Alex Row and New Zealand's Luke Mathews.
In the women's 200m Olympic 100m hurdle champion was defeated by Ella Nelson y Melisa Breen.
Elswhere on the track, threw Mathew Outzen threw 81.80m and defeated Hamish Peacock 80.32m in the javelin.
In the men’s high jump Australian Brandon Starc cleared a personal best of 2.30m to beat Canada’s 2.40m man Derek Drouin and his teammate, Michael Mason, who both cleared 2.28m.
In the men's 1500m race Australias Ryan Gregson outsprinted teammate Jeff Riseley to win the race in 3:36.51. American Andrew Wheating took third in 3:38.75.