Russia's Karatsev seals maiden ATP title
Stay tunned with 24 News HD Android App
The 27-year-old, who became the first man to reach the semi-finals on their Grand Slam debut in the Open era at the Australian Open last month, cruised past South African Harris 6-3, 6-2.
"I did a good job with my team, with my coach and it has happened now."
Karatsev, who climbed from 114th to 42nd in the world rankings following the Australian Open, broke qualifier Harris' serve midway through the opening set and twice more in the second.
It was his first ATP singles final, having won an event for the first time on tour in last week's doubles tournament in Doha, alongside compatriot Andrey Rublev.
He dumped out the in-form Rublev in Friday's semi-finals and backed that up against Harris.
Karatsev saved the only two break points he faced as he raced to victory in under an hour and 20 minutes.
"I am super happy. It was a tight match. (I was) really nervous," added Karatsev. "I want to congratulate my opponent for the final (run). He did a great week... I am happy that I won."