Emma Raducanu fought back at the Transylvania Open to earn her first win since becoming the US Open champion.
But the world number 23, seeded three in Romania, had the perfect response against Slovenia's Polona Hercog, 30.
Playing in her father Ian's homeland for the first time, Raducanu won 4-6 7-5 6-1 to move into the second round.
Despite being a Grand Slam champion, this was her first WTA tour win and although no fans were allowed in Cluj-Napoca due to Covid-19 restrictions, her 88-year-old grandmother Niculina, who lives in Bucharest, was present for the hard-fought victory.
Raducanu smiled and laughed throughout her post-match interview, during which she spoke almost entirely in Romanian and was even asked about her favourite local dish.
"This means a lot to play in my dad's country," she said. "It feels like a huge win.
"It is a shame there aren't fans here, but I hope they were watching and I just wanted to do them proud.
"I was on a losing streak so I am really pleased to have come through that. It's my first win, I knew that in my head, so I was battling really hard to get on the board."
Raducanu, still looking for a new coach after parting with Andrew Richardson following her US Open triumph, asked for patience before the WTA 250 event.
Yet, playing a far more experienced opponent in a match lasting two hours and 29 minutes, she managed to prevail.
The teenager charged into a 3-0 lead, but Hercog, ranked 124 in the world, won both of her break points to fight back and take the last five games of the first set.
Raducanu regrouped in the second and began to show some of the grit and shot selection that led her to that thrilling victory in New York.
Hercog staved off three break points in the fourth game of the set, before Raducanu saved one in each of her last two service games to make it 6-5.
The Briton then clinched the set after Hercog sent a forehand long on the last of three break points, before breezing through the first five games of the third set.
Hercog finally held serve after saving two match points and had a break point in the next game, but Raducanu recovered to win it with an ace and set up a match with Romania's world number 106 Ana Bogdan, 28.
"I am really proud of how I fought," Raducanu added. "That is a big learning thing for me.
"The key was to try to stay mentally composed. I knew I wasn't playing very well so I just needed to keep going one point at a time and giving myself a chance by holding serve."
Norrie wins in Vienna
Cameron Norrie continued his winning streak by beating Marton Fucsovics 7-6 (4) 6-1 in the first round of the Vienna Open.
The British number one was playing his first match since his breakthrough victory at Indian Wells earlier this month and the 26-year-old came out on top against the Hungarian for a seventh straight success.
It was also Norrie's 11th in 12 matches and the world number 14 will play sixth seed Felix Auger-Aliassime of Canada in the next round.