Alexander Zverev denied Richard Gasquet a third consecutive Open Sud de France title and was also crowned doubles champion on a day in which Grigor Dimitrov won the Sofia Open in his homeland.
Gasquet has become accustomed to success in Montpellier, winning the title on home soil in three of the last four years, but teenager Zverev dethroned the classy Frenchman with a 7-6 (7-4) 6-3 success on Sunday.
Not content with winning his second ATP singles title, the Next Generation star teamed up with his older brother, Mischa, to beat Fabrice Martin and Daniel Nestor in the doubles final later in the day.
The 19-year-old is the first player to win a singles and doubles title at the same tournament since Lleyton Hewitt achieved that feat at Newport three years ago.
Fourth seed Zverev broke Gasquet in the first game of the match and took charge of the tie-break after his more experienced opponent had hit back to level at 2-2.
The German youngster gave himself the chance to serve out the match by coming up with the only break of the second set to lead 5-3 and duly seized his opportunity.
Dimitrov gave another indication that he is ready to make further strides this season by beating David Goffin 7-5 6-4.
The powerful third seed dropped just one set this week and now has two titles under his belt in 2017 after seeing off Goffin, who was broken five times.
His record for the year now stands at 14 victories and just one defeat, which came against Rafael Nadal in the semi-finals of the Australian Open.