Estoril - Teenaged Borna Coric secured the first upset of the week at the re-launched Estoril Open on Monday with his 6-2, 6-4 knockout of French sixth seed Jeremy Chardy.
The youngest player in the field, debuting at the event, celebrated his success on the same day as fellow prodigy Nick Kyrgios of Australia left his teen years behind, turning 20 with a practise session and a meal at the Club de Tenis do Estoril with his coaching team.
Tweets were plentiful as the 46th-ranked Kyrgios, seeded seventh, prepared for his second clay match of the season against Spaniard Albert Ramos-Vinolas at a tournament now under fresh German-Portuguese management and being staged at a new venue.
The Australian lost in the Barcelona first round last week after holding two match points against Swedish qualifier Elias Ymer.
Kyrgios has been injured for much of 2015, compiling a sparse 5-3 record this season, with Barcelona his first event in well over a month since an ankle injury suffered in March on Indian Wells' hardcourt.
Coric levelled his record with Chardy at 1-1 after losing to the number 32 in the Australian Open first round. He next faces Portuguese competition as he waits for a winner from Joao Sousa and wild card Rui Machado, a quarter-finalist five years ago.
"I had a practise match with Sousa in Miami, I think I lost a set 6-4," said Coric. "Either one of those guys will be tough, they are both playing at home and guys usually play better in from of the home crowds.
"I'll try my best and see what happens."
Coric said that he was not feeling at his best during practise, but lifted with perfect timing for his 93-minute win.
"I was struggling in practise, I was not feeling the ball. I was scared of how I would play in the match, but I played well after all.
"There was a bit of wind but that is to be expected here," said the tournament debutant. "I was playing very good tennis, it was a good match for me."
Coric broke for 2-1 in the opening set on the clay, enough of a margin to win the opener. He went down a break early in the second, got it back and broke again for 5-4 before serving out victory a game later on the first of two match points.
Dutchman Robin Haase won his fourth match of the season and first on clay with a defeat over Ricardas Berankis of Lithuania 6-3, 6-7 (6/8), 6-4.
Haase now moves to the second round, to face Spain's Feliciano Lopez, playing as a tournament top seed for only the fourth time in his career.
Filip Krajinovic of Serbia put out Alejandro Gonzalez 6-3, 6-3 while eighth seed Gilles Muller of Luxembourg defeated local wild card Federico Ferreira Silva 6-3, 3-6, 6-1.
Collated results on the first day of the ATP Estoril Open on Monday (x denotes seeded player).
Borna Coric (CRO) bt Jeremy Chardy (FRA x6) 6-2, 6-4
Robin Haase (NED) bt Ricardas Berankis (LTU) 6-3, 6-7 (6/8), 6-4
Filip Krajinovic (SRB) bt Alejandro Gonzalez (COL) 6-3, 6-3
Gilles Muller (LUX x8) bt Federico Ferreira Silva (POR) 6-3, 3-6, 6-1