Britain's Johanna Konta praised the help of a psychologist for settling her nerves after clinching the second grand slam victory of her career against Louisa Chirico at the US Open.
Konta had reached round two of a major tournament only once before, at Flushing Meadows in 2012, and she repeated the feat with a convincing 6-3 6-0 win over the American wildcard.
Britain's Aljaz Bedene is also through after his opponent Ernests Gulbis retired injured but there were first round defeats for Laura Robson, who lost to Elena Vesnina, and James Ward, who was beaten by Brazilian Thomaz Bellucci.
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Konta's win means she has now managed 14 consecutive victories and the 24-year-old will face either ninth seed Garbine Muguruza or Germany's Carina Witthoeft in the second round.
The British number two has always been a sound hitter from the baseline but has previously struggled for the power and, more particularly, mental toughness to capitalise on winning positions.
Leading 5-2 in the first set against Chirico, it seemed tension might take over again when the American clawed a game back and opened up 0-40 on the Konta serve, but the Briton regained her composure to come back and serve out.
When asked about the cause of her hot streak, Konta pointed to "mental coach" Juan Coto, a friend of her Spanish coach Esteban Carril.
Coto is usually employed by hedge fund managers and city workers but he has been helping Konta since the end of last year.
"The big thing is being able to relax," Konta said. "It's not about releasing (the tension), it's about managing it.
"I'm a certain personality and it's about taking the goods from that but also managing the things that aren't so helpful.
"I'm happy with how I'm managing things, more so now than before. It didn't just click, it's something I need to work on and make into a habit."
Closing out a winning position proved problematic too for Robson, who threw away a 4-0 lead in the deciding set against world number 108 Vesnina to lose 3-6 6-3 7-5.
Robson is still in the early stages of her comeback following 18-months out with a wrist injury, but after an upturn in form there was optimism she could record a first grand slam win in two years.
"Any loss is tough but that one especially, because if we're being honest I should have won," Robson said.
"In the third set, I gave myself the best chance to win the match by going 4-0 up but then for some unknown reason decided to let her lose the match rather than me go out and win it.
"I didn't feel overly nervous but I just took five per cent off all my shots and that was enough to let her back into the match.
"She wasn't going to give up, so that five per cent made the difference and it didn't work out."