Rune broke Tsitsipas' serve in the third game of both sets and saved the only break point he faced en route to his second career ATP Tour title in one hour and 35 minutes.
Rune produced 20 winners and 13 unforced errors, compared to 16 winners and 11 unforced errors for Tsitsipas. Both men had three aces.
Tennis Napoli Cup
Fourth-seeded Lorenzo Musetti(20) defeated fellow Italian and numnber two seed Matteo Berrettini (26) 7-6 (5), 6-2 to pick up his second career ATP Tour title in Naples, Italy.
Musetti won 85% of his first-service points (35 of 41) and saved the lone break point that he faced during the two-hour, two-minute match. Musetti converted two of his seven break chances.
Musetti finished with 15 winners (including four aces) and only three unforced errors. Berrettini had 16 of each and double-faulted four times.
European Open
Numner two seed Felix Auger-Aliassime (22) of Canada collected his second straight trophy and third career title with a 6-3, 6-4 victory against unseeded American Sebastian Korda (22) in Antwerp, Belgium.
Auger-Aliassime struck seven aces, saved both break points he faced and finished with only five errors compared to 23 winners in the 83-minute match.
Korda finished with 10 winners and 11 unforced errors and won only 57% of his points at the net (8 of 14).