Andrea Petkovic is starting to see the results of a coaching change earlier this year.

The German hired veteran coach Eric van Harpen last month but struggled in a few tournaments, losing winning just one match through Dubai, Doha and Indian Wells. She lost in the second round of Miami to Alize Cornet.

"I changed my coach, obviously, and I expected everything going really well, and then I played bad in Dubai and Doha and Indian Wells, and Miami I played a little better," she said.

Reaching the final at Charleston, however, tells the former world No. 9 she is on the right track.

"I think I've made the right decision, but now this is sort of the confirmation for it," she said, adding that she was taking a more attacking, varied approach.

"It's going really well, because I think he's bringing another level to my game. He's really behind me trying to play more margin over the net and go for more with the serve and step in, taking the ball early, going through to the net."

After returning last year from a knee injury, Petkovic returned to the Top 40 with Petar Popovic but wanted more professional distance.

"With Petar I was with for so many years, and I miss him in my team because he's such a positive energy," Petkovic said. "But you know, sometimes when you're also really close friends, you lose that coach-player relationship, and so I felt like I needed a change, and now I think I'm happy with everything."