Praggnanandhaa won with 7.5 points from nine rounds.
The top-seed was in fine form and remained unbeaten through the nine rounds. He finished the tournament with a win over fellow Indian V Praneeth, an International Master, late on Friday.
Praggnanandhaa (Elo 2642) finished a full point ahead of second-placed IM Marsel Efroimski (Israel) and IM Jung Min Seo (Sweden).
V Praneeth with six points was joint third but was placed sixth due to an inferior tie-break score.
Apart from beating Praneeth, Praggnanandhaa posted wins over Victor Mikhalevski (in round 8), Vitaly Kunin (round 6), Mukhammadzokhid Suyarov (round 4), Semen Mutusov (round 2) and Mathias Unneland (round 1).
The GM will be part of the India B team in the open event of the 44th Chess Olympiad in Chennai next month.
Praggnanandhaa's coach R B Ramesh congratulated him after the win and said it will help boost his confidence.
In May, Praggnanandhaa Rameshbabu posted his second win over world champion Magnus Carlsen in the Chessable Master online event. The two players met in the 5th round of the Chessable Masters online rapid chess tournament and Praggnanandhaa kept his chances alive of progressing to the knockout stage after the win over Carlsen.