Buckman stopped the clock at 4:04.09 to take almost a second off her personal best set at last year's world championships in Moscow.
The performance came on the famed Hayward Field, which Buckman knows well from the time she spent at the University of Oregon. Since then she has joined up with Nic Bideau's Melbourne Track Club and become competitive on the world stage.
“I feel like a completely different athlete now compared to when I lived as a student in Eugene, competing at Hayward Field back in 2011. Then I was along for the ride, now it's about being a contender,” Buckman said prior to the race.
“I am taking one race a time, it is all you can do when you are racing and training on different continents like I do. I would like to put in a strong performance this weekend and then win more races in Europe. I want to run a sub 2-minute 800m and in Glasgow I want to finish knowing that I have done everything I could have to come home with a medal."
Across in Europe another Bideau coached athlete, Genevieve Lacaze, lowered her personal best in the 3000m steeplechase to all but secure her place in the Commonwealth Games team.
Lacaze finished second in the Flanders Cup Meeting in Oordegem, Netherland in 9:37.16.
Lacaze has improved in virtually every race this season after a disastrous ankle injury abruptly ended her 2013 season. Commencing with a 4:29 1500m in Hobart in February, the 24-year-old finished the domestic season with a bronze medal at the national championships.
Selectors now have the option of selecting two of Kaila McKnight, Melissa Duncan and Bridey Delaney alongside Buckman in the 1500m. In the steeple Lacaze and Madeleine Heiner are likely to join with the already selected Victoria Mitchell.
Back in the US, Collis Birmingham finished 12th in the 5000m in 13:27.17 while Ryan Gregson finished just a second outside his personal best for the mile in finishing sixth in the B-race in 3:53.85.