Heather Watson edged out by Mona Barthel in Quebec

British number one Heather Watson has exited the Bell Challenge in Quebec at the first-round stage.

The 19-year-old gave third seed Mona Barthel a scare when she took the opening set 7-5 in a tie-break.

German Barthel responded by winning a second-set tie-break by the same scoreline, before taking the final set 6-1 to complete her victory in two hours and 38 minutes.

Watson is ranked 72nd in the WTA rankings - 36 places below Barthel.