STANFORD (REUTERS) - Madison Keys outduelled fellow American Coco Vandeweghe 7-6 (6-4), 6-4 on Sunday to win the Stanford Classic and capture her first title of the year.

In an evenly-matched contest between two friendly opponents, third seed Keys was impregnable on serve, but claimed the only break in the second set before closing out a confidence-boosting win ahead of the US Open.

Keys missed the opening two months of the season after undergoing surgery on her left wrist, but has worked her way back into solid form, knocking out Wimbledon champion Garbine Muguruza in the semi-final.

"It hasn't been the easiest season, but it finally feels like I'm on the right track and feeling good about my tennis again," Keys told reporters.

"It feels amazing to have a title at home and on hard courts. I'm really, really happy that this is kind of the start of my US Open Series."

Vandeweghe, who reached the semi-finals of the Australian Open and the quarter-finals at Wimbledon this season, was also looking for her first title of 2017.

She blasted six aces, but faltered in the opening set tie-break to allow Keys to take control.

"I think it was a high quality match from both players. It was fun to play a friend, to have an all-American final - it was enjoyable," Vandeweghe said.