British number one Johanna Konta's US Open preparations continued with a second straight defeat as she lost in the Cincinnati Masters first round.

Konta, 28, was beaten 6-3 3-6 7-5 by Swedish qualifier Rebecca Petersen.

The world number 14 trailed 4-1 in the final set but recovered to level at 4-4 before Petersen took her fourth break point of the match to seal victory.

Konta lost to Ukrainian teenager Dayana Yastremska in the first round of the Rogers Cup in Toronto last week.

Meanwhile, seven-time Grand Slam champion Venus Williams, 39, ended a four-match losing streak by beating fellow American Lauren Davis 7-5 6-2.