Basilashvili, who was seeded fourth at the clay-court event, is ranked 16th in the world but will lose points because last year he took the title after coming through qualifying. 

The 27-year-old's only other ATP Tour title came in the hard-court China Open in Beijing last October.

The Georgian dropped serve early in the first set but broke back with his sixth break point of the sixth game. He wasted a set point in 10th game before clinching on the fourth break point of a marathon 12th game.

The 21-year old Rublev hit back with the only break of the second set to level the match.

Basilashvili broke in the second game of the final set. Rublev hit back at once but Basilashvili immediately broke again. The young Russian took the next game to deuce but the Georgian held and was in control the rest of the way.

Basilashvili upset Hamburg native and second seed Alexander Zverev in the semi-finals.