BRITAIN’S Jo Konta likes to talk about “progression” when describing her career path but if she goes much further here at the US Open, she might have to add meteoric to her vocabulary.

Having come through qualifying to make the main draw, the 24-year-old took out Germany’s 18th seed Andrea Petkovic 7-6, 6-3 yesterday to reach the fourth round of a Grand Slam for the first time.

Though Petkovic had treatment in the second set and admitted later she’s been struggling with a cold, the German was outplayed by Konta, who finally got over the line on her sixth match point.

Until this week, Konta had won just one main-draw match at a Grand Slam but she showed in reaching the quarter-finals at Eastbourne this summer, beating Garbine Muguruza and Ekaterina Makarova along the way, that she has the game.

What’s changed is confidence and in addition to the two ITF titles she picked up along the way to the US Open and her seven wins to this point, she’s now won 16 straight matches.

Despite looking a little nervous at first, when she fell 2-0 down, Konta produced a mature performance, shrugging off the disappointment of twice losing a break of serve lead to close out the first set on the tiebreak.

Petkovic, whose game style is eerily similar to that of Konta, called for the trainer at 3-0 down and took some more painkillers and had her blood pressure taken.

She continued to fight and made life difficult for Konta as she tried to close it out, saving three match points at 5-1 and two more at 5-3 before getting over the line when the German pulled a forehand wide.

“It was definitely tough because even if she is not feeling at her best, she is still one of the best competitors on the Tour,” Konta said. “She definitely didn’t give it to me in the end as you could tell from the last three games.”

“I feel I’ve been playing a good level of tennis the whole year. I’m lucky enough that I’m healthy enough to continue and play as many tournaments as I want. But of course it’s always a confidence boost when you get to compete against the best players.”

The victory will take Konta from her ranking of 97 into the world’s top 60 and should she manage what would be a huge upset in the fourth round, against the two-time Wimbledon champion Petra Kvitova, she would break the top 50 and be the first British woman to reach the last eight of any Grand Slam for 31 years.

Konta says it’s coincidental but her improvement seems to have come around the same time as the Lawn Tennis Association announced they would be cutting funding to the top players.

For Konta, who has spent much of the past three years just outside the world’s top 100, it was a blow, but her form, from the grass court season onwards, shows how well she has responded.

“It’s never nice to feel like your career could be in jeopardy, so I don’t think that’s beneficial at all,” Konta said.

“It has definitely brought some uncertainty to things but I was always going to find a way.

“It’s not like I’ve been completely let go but it definitely brought some change to my circumstances. But change is sometimes needed as well and it gave me the opportunity to go to Spain a bit more, get a change of scenery.

“I think what has been beneficial is just the team I have around me and the environment they’ve created for me, so I am very grateful for that and just really enjoying the place I’m in with them, the journey that we’re on and the things that we’re working on”.

Kvitova has been sneaking through the draw without too many eyes on her, which is just the way she likes it.

The US Open is the least successful of the four Grand Slams for Kvitova but the Czech looked particularly impressive as she beat Anna Karolina Schmiedlova of Slovakia 6-2, 6-1.

Kvitova announced last month that she has been suffering the after-effects of mononucleosis, or glandular fever, and has been practising less between matches in an effort not to over-do things.

“Every match I play and win is a bonus,” she said. “Mentally, I’m feeling great. That’s important and probably why I played the way I played today.”

Eugenie Bouchard may be forced to pull out of her fourth-round match with Roberta Vinci, today, after falling over in the locker room and hitting her head. Tournament organisers said the Canadian had withdrawn from the mixed doubles and women’s doubles and would continue to be assessed.