"This win is for all of Ethiopia. I was trying to control the race coming from the first place during the run so it was very hard for me ... I felt in shape and my victory confirms it was a good plan."
Kenyan Beatrice Chebet moved up in the final 200m for silver and Ethiopian Dawit Seyaum finished with bronze.
"It was a matter of tactics. I was well positioned," said Chebet. "This medal will make a good difference for me."
It was the fourth gold for Ethiopia in Eugene, Oregon, who have 10 medals total and sit behind the US in the medals table.
Seyaum, who kept Doha silver medallist Margaret Kipkemboi off the podium, said it was a special performance for her after dealing with injuries for five years. "I hoped and I also expected to become a medalist in this event. So I trained well and prepared myself hard for any kind of a medal," she told reporters.
Hassan had played down expectations ahead of Eugene, having scarcely competed after the mental and physical exhaustion of her remarkable distance double at the Tokyo Games, and told reporters she had only began to train about two months ago.
"I did my best and I gave everything. I did the race smart, did not make any mistake," she said. "I wanted to get a break for my mental part because athletics is not only about running but also about motivation. It is so hard to get motivated again. I took almost seven months break. I am happy to be back and I will try for more golds next year."
After the race a fan ran onto Hayward Field holding what appeared to be a Tigray flag and picked up both Tsegay and Gidey before being removed by security.
A conflict erupted in November 2020 between rebellious forces from the Tigray region and the Ethiopian government.