Olympic 800m champion and world record holder David Rudisha was dethroned by his young rival Nijel Amos as the 20-year-old took the Commonwealth title in style.
Amos, who won silver in London in the greatest 800m race in history, kicked hard down the home straight to overtake Rudisha and cross the line with his arms outstretched in celebration.
Rudisha as always went to the front at 150m and tried to control the race from there, just as he had in setting that phenomenal record in 2012.
But, after a 2013 wrecked by a knee injury and a summer where he has been chasing fitness as well as his rivals, he could not take it out fast enough. He was powerless as Botswana's Amos accelerated past him with 50m to go to take gold in one minute 45.18 seconds.
Rudisha's 1:45.48 won him silver with Amos's South African training partner Andre Olivier taking bronze, Scotland's Guy Learmonth running a brilliant personal best of 1:46.69 for sixth and England's Michael Rimmer, after an injury-ravaged season, two hundredths of a second further back in seventh.
The 25-year-old Rudisha had gone through 400m in 52.7 seconds, more than three seconds down on his split from the Olympic final.
And it was that comparative lack of gas that allowed Amos, his country's flag-bearer at the opening ceremony, to come through the traffic down the finishing straight to repeat his victory at the Monaco Diamond League.
|BBC athletics commentator Brendan Foster:|
|"The proud Maasai warrior David Rudisha needed different weapons for this event because in London he didn't come under pressure, but here he did. It looked as though Nijel Amos was trapped, but when they came on the straight Amos was determined to beat the great man. Rudisha wasn't able to do it tonight because he wasn't fit enough. Amos has beaten a man who he admires so much."|
Amos told BBC Sport: "I am so happy but David Rudisha will always be the hero of 800m."
It had been billed as one of the races of the Commonwealths, one of the few in which the best in the world has been challenged by a talent only fractionally behind.
Rudisha was given a reception befitting a great champion by a capacity Hampden crowd, and in defeat he showed characteristic grace despite the disappointment.
"The race was good, but in the last 100m I found it a little bit difficult," he said.
"He is a tough competitor. We ran a tactical race, but he was good tonight."