CINCINNATI, OH, USA - Sweden's Rebecca Peterson scored the second Top 20 victory of her summer in the first round of the Western & Southern Open on Monday, as she outlasted No.14 seed Johanna Konta of Great Britain, 6-3, 3-6, 7-5.

The Swedish No.1 had been 0-8 against Top 20 opponents before upsetting then-World No.8 Sloane Stephens at the Citi Open two weeks ago, and scored her second victory over an elite opponent in the first round of Ohio's Premier 5 event. 

"I'm pleased with the result. I'm happy with the way I'm playing, but I want to go further and I want to do better," Peterson said after the match. 

"It was a battle the whole match pretty much. I'm really happy with the way I was fighting for every point, and I had to. She was playing really tough, and I'm just really happy that I went through."

Peterson claimed 62 percent of points off of Konta's second serve during the two-hour and 33-minute barnburner, and Konta was undone by 45 unforced errors throughout.

Peterson lost just three points on serve in the opening set, as she made a break in Konta's first service game stand up with ease.The Swede landed 70 percent of her first serves in the opener, hit two aces and tallied a trio of love holds, including her last to seal the set. 

Konta rebounded in the second set, claiming the sole break to garner a 4-2 advantage. Serving for the set at 5-3, Konta had to stare down a break point before closing to level the match.

The Brit broke Peterson in the first game of the decider before the Swede went on a run, reeling off four straight games to collect a 4-1 lead. Peterson then held five break points to go up 5-1, but Konta staved each one off to hold for 4-2 and stay within touching distance.

Konta then got back on serve in the following game, eventually staying level with Peterson up through 5-5. But after the Swede held for 6-5, Konta lost the plot and quickly fell behind 0-40 after a clutch of errors. Peterson needed a single match point to finish off her win, after Konta fired a forehand wide to end the affair.

"I know that I have the game inside of me and that I can beat the top players," Peterson said. "I'm just, one day at a time, trying to get better all the time, and just keep on improving, and hopefully, the results will come."

The Swede, who came through the qualifying, will face a fellow qualifier in the second round: Russia's Veronika Kudermetova, who defeated American wild card Bernarda Pera, 6-2, 6-3.

"I've played her before, two times," Peterson, who is 1-1 against the Russian, recalled. "It's going to be another tough match and I'm looking forward to the challenge."