"It means a lot," said the Czech after winning her sixth title on Saturday.
"It was a great week and I was improving in every game. Today, I showed my best tennis.
"Iga motivates me every day, it was a great final and I'm definitely happy with the result."
Victory meant former world No.2 Krejcikova became only the fifth player to defeat the top three in the world at the same event.
The Czech began in dominant fashion by breaking in the first game with a searing crosscourt backhand winner.
A loose game allowed Swiatek to draw level at 3-3 but the 2021 French Open champ Krejcikova struck back immediately with aggressive ball-striking, only to then surrender her serve again.
Krejcikova took the next game to love as Swiatek struggled to contain the unforced errors and the 27-year-old held firm to wrap up the opening set when the Pole sent a forehand long.
It was the first set that Doha champion Swiatek had dropped in the past two weeks and the 21-year-old found herself trailing 4-2 in the second set as Krejcikova took control.
Krejcikova, who defeated Australian Open champion Aryna Sabalenka in the quarter-finals and third-ranked Jessica Pegula in the semis, closed out the match on serve to join an elite club.
Steffi Graf, Serena Williams, Venus Williams and Sabalenka are the only others who have beaten the top-three ranked players in the same tournament.
"It's a huge achievement," Krejcikova, who won her first WTA 1000 title, added.
"I was enjoying all the matches and I love playing on big courts with the great atmosphere. I hope there's going to be more matches like this for me."
Krejcikova is set to climb from number 30 to 16 when the rankings are updated on Monday.Â
