Alex de Minaur has been beaten in straight sets by Briton Kyle Edmund in the second round of the Estoril Open.
The teenage Australian, who was granted a wildcard into the tournament, lost 6-2 7-5 to the third-seeded Edmund in an hour and 37 minutes.
World No.23 Edmund surged to a commanding set and 4-2 lead before 19-year-old de Minaur fought back to win the next three games.
However, Edmund broke again at 6-5 before serving out the match.
"I think I played a good match because de Minaur is a really good competitor and he moves well," Edmund said.
"It was a quality match."
Edmund will play Portugal's No.1 singles player Joao Sousa in the last eight.
The 'Conquistador', as he is affectionately known by the home crowd, beat compatriot Pedro Sousa 4-6 7-6 7-5 to advance.
American Frances Tiafoe made it through to the quarter-finals with a straight sets win.
The 20-year-old, who won his first senior ATP title at the Delray Beach Open in February, dispatched fourth-seeded Gilles Mueller with a 6-4, 7-5 victory.
Italian qualifier Simone Bolelli will play Tiafoe in the last eight after he overcame Argentine Federico Delbonis 3-6 7-5 6-2.