Aljaz Bedene has won his first match since becoming a UK citizen and taking up the position of British number two behind Andy Murray.
The Slovenia-born 25-year-old beat France's Maxime Chazal 6-3 6-2 in the first round of qualifying for the clay-court Casablanca Open in Morocco.
Bedene, who moved to the UK seven years ago, attended a citizenship ceremony last Tuesday.
He is ranked 83rd in the world, ahead of James Ward in 111th place.
On seeing 'GBR' next to his name in the Casablanca schedule, he wrote on Twitter: "It's taken a while to get to this but it's awesome to see."
After the victory over Chazal, he added: "Happy to get the first match out of the way. Was solid to be fair and more to come which is always good. Looking forward to the next one.
"Thanks for all the support and love guys, I feel really lucky."
Bedene reached his first ATP final in India at the start of the year, beating top-20 players Roberto Bautista Agut and Feliciano Lopez along the way.
He hopes to play for the Great Britain Davis Cup team, although he has already represented Slovenia and current rules prohibit a player appearing for two nations.
"He's a good player with a very good serve," Murray said in Miami last week.
"He's a legitimate top-100 player. When he plays challengers he's there or thereabouts; when he plays on the main tour he wins matches. It's not like he turns up and always loses in the first round.
"I would imagine he's going to be comfortably in the top 70 or 80 in the world for a while."
Bedene is the top seed in Casablanca qualifying and will play Austria's Michael Linzer or Frenchman Maxime Texeira in the second round.