NEW YORK—Eugenie Bouchard says she is gaining confidence following an extended slide down the rankings this season.

Bouchard won her second-round match at the U.S. Open over Polona Hercog, 6-3, 6-7 (2), 6-3, to record two match wins in a row for the first time since Indian Wells.

The 21-year-old Canadian said she was particularly pleased that she kept her lead in the third set, having allowed opponents to come from behind and win multiple times this season.

"It's like a huge deal," she said. "Just confident that I believed in myself in the third. Even when things got tough, I kept the confidence up and the belief. Tried to keep myself going energy-wise. Those are all things that I think helped today. Those are all things that I didn't do so well in past matches."

Bouchard, who has played much of the season with an abdominal tear, is also encouraged she that is injury-free.

"Coming into this U.S. Open I've been healthy, so that's I think the biggest point," she said. "I think all the other Slams this year I had a few things here and there. Didn't get the preparation I needed to. Coming into this Slam, I feel like I did. Even though I didn't play as many matches as I wanted to, I was getting the practice in. That also helps with your confidence, knowing everything's good with your ball."

Bouchard plays Dominika Cilbulkova in the third round.