The Spaniard, ranked 24 in the world, ground out a hard-fought victory in three sets against the Czech Republic’s Tomas Berdych, winning 6-4, 3-6, 6-3 in the final.
“It’s been a fantastic week for me,” he said immediately after his triumph.
“Today it was not easy to manage all the emotions I had on court.”
It was the 30-year-old’s ninth career title and his first in Doha.
The victory came 24 hours after he beat Djokovic in the semi-final, also in three sets.
He also beat three-time Grand Slam winner Stan Wawrinka in straight sets earlier in the week.
In total, Bautista Agut only lost two sets all week in his five matches.
The Spaniard made the decisive break of serve in the third game of the final set to take a lead he never lost.
Wildcard Berdych threatened to break back but squandered two points on Bautista Agut’s serve in the seventh game.
“Roberto was too good, so well done for the title today, but I am happy for the week,” said Berdych, whose 2018 season was blighted by a back injury.
The defeat was the second time Berdych has lost in the Qatar final, the first occasion was in 2015 to another Spaniard, David Ferrer.
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