Tsitsipas is only the second top seed in the tournament's five-year history to win the title
World number 10 Stefanos Tsitsipas captured his third ATP title after beating Uruguay's Pablo Cuevas 6-3 7-6 (7-4) to win the Estoril Open.
The 20-year-old top seed was coasting to the title leading by a set, up a break and serving at 4-3 in the second.
He was broken for the first time, losing nine consecutive points, but saved a set point and went on to wrap up the match in an hour and 43 minutes.
It was his first clay court title, his second this season and first outdoors.
Tsitsipas, who beat Roger Federer en route to the Australian Open semi-finals in January, became the first Greek player to win an ATP World Tour title when he claimed the Stockholm Open in October and he added the Open 13 Provence title in Marseille in February.
Victory in his second meeting with Cuevas maintained his 100% record against the Uruguayan, who was seeking a seventh ATP title.
