US Open 2019 news - Johanna Konta into second round after battling victory over Daria Kasatkina

Konta cruised through the opening set against the world No 42 and looked set for a comfortable victory but dropped her level to lose the second and her composure midway through the match.

However, she found her range again in the final set as Kasatkina's serve fell apart and claimed victory after two hours and four minutes, her first victory on the hard courts this summer.

“I thought I started really well and she didn’t start as well. I capitalized on that,” Konta said.

“Then in the second set she raised her level.

“She’s no walk in the park. I knew that her game was going to be tough for me to play against.

"I was accepting it was going to be a long, tough match and that’s what it was. I’m pleased I was able to adapt as the match was going.”

Konta had made the perfect start to the match - or rather Kasatkina made an imperfect one: the 22-year-old double-faulted twice in the opening game to hand the Brit an early break.

She might have been further ahead two games later when another double fault gave her a 0-30 lead on her opponent's serve but on this occasion she was not able to capitalise.

However, opportunities were not few and far between and by the seventh game, Kasatkina was hitting 78 miles per hour first serves into the net and soon lost the first set 6-1 in just 25 minutes.

Konta was asserting herself from the baseline whenever possible, hitting 10 winners in the opening set and allowing the Russian only three, while also keeping the points short despite tricky, blustery conditions.

A fresh set did seem to give Kasatkina some fresh hope and Konta was forced to save a break point at 1-1, but did so brilliantly by adjusting to put away an awkward backhand at the net.

But the Russian would not go away and began to find her feet, benefiting from two missed overhead smashes by Konta, finally securing her first break of the match for a 3-2 lead in the second.

The sea change continued with Konta's unforced error habit rearing its ugly head as she hit 14 in the first six games of the second set.

Briefly, the world felt against Konta as line calls and decisions went against her and when Kasatkina saved four break points at 4-3, in a game when the umpire had to overrule multiple calls on the court, she lost her temper somewhat and dropped the second set soon after.

The British No 1 took herself off court before the decider which turned out to be a ding-dong affair with three breaks of serve in the opening four games, two of them going Konta's way, the last two love; it felt decisive and so it proved.

Soon after, the double faults returned to Kasatkina's game and Konta found her rhythm from the baseline again, eventually sealing the match in just over two hours courtesy of back-to-back double faults from her opponent.

Konta will now face either Russia's Margarita Gasparyan or Australia's Priscilla Hon for a place in the third round.