The Mumbai teenager claimed the first Tour title of the year when he despatched top-seeded Scot Greg Lobban in the final of the Open du Gard, the PSA Challenger 5 squash event marking its sixth year at Squash des Arenes here.
Third seed Mangaonkar made his breakthrough in the semi-finals when he crushed second-seeded Kuwaiti Ammar Altamimi in just 28 minutes.
Now in the fourth Tour final of his career, the 19-year-old had a point to prove when he faced Lobban, a 21-year-old from Edinburgh enjoying his eighth Tour final.
Revenge looked on the cards when Lobban took the opening game, but Mangaonkar struck back to win the next three to claim his 9-11 11-3 11-4 11-5 title triumph in 64 minutes.
More From This Section
The win, his third on the PSA Tour, also set up a nine-match winning streak for the Indian - the longest of his career.
"First win of 2014 in Nimes," Mangaonkar wrote on his Twittr account. "Hopefully more to come this year. Now preparing for German League in January and Finland next month."
1st round:
[3] Mahesh Mangaonkar (IND) bt [Q] Ollie Holland (ENG) 11-4 retd.
Quarter-finals:
[3] Mahesh Mangaonkar (IND) bt Youssef Abdalla (ENG) 11-6 8-11 11-4 11-5 (54m)
Semi-finals:
[3] Mahesh Mangaonkar (IND) bt [2] Ammar Altamimi (KUW) 11-9 11-2 11-0 (28m)
Final:
[3] Mahesh Mangaonkar (IND) bt [1] Greg Lobban (SCO) 9-11 11-3 11-4 11-5 (64m).