It was Hassan's second gold medal of the championships following her win in the 10,000m, making her the first woman to successfully double in the two events. It capped a tumultuous week for Hassan, who was left stunned after Salazar's four-year doping ban was announced on Tuesday. Salazar was barred from the championships following the ban and his athletes from the Nike Oregon Project training group were ordered to immediately cease all communication with him.
"It's a very hard week for me," Hassan told the BBC.
"I was so just angry and I could not talk to anyone. I just ran all out. That hard work can't be beaten by anything.
"It's what makes me angry, I have been clean all my life. I work hard, I'm not an emotional person but it makes me so mad."
Hassan had run a masterful race. After taking her time at the back of the pack, she hit the front towards the end of the first lap and was always in control at the Khalifa Stadium.
Britain's Laura Muir was on her shoulder at the bell but Hassan turned on the speed with around 250m to go to put clear daylight between her and the rest of the field, finishing around 20m ahead of Kipyegon.
Hassan had startled many at the start of the championships after her win in the 10,000m, showing a devastating turn of speed over the closing laps to take gold.
However she found herself at the eye of storm on Tuesday when news of Salazar's four-year suspension rocked the championships.