The US Open champion came from a set down to win.
Poland’s Hurkacz, making his tournament debut in Turin took the first set on a tie-break.
But US Open champion and world number two Medvedev hit back to claim a 6-7 (5) 6-3 6-4 la victoire.
The Russian has now won 23 of his past 26 matches, and made it six consecutive victories at the season-ending ATP Finals.
Medvedev did not face a single break point in the match and won 83 per cent of his first-serve points with 15 aces.