Heather Watson climbs into top 50 following victory at the Japan Open

Heather Watson celebrates victory in the Japan Open (GETTY IMAGES)

Heather Watson has climbed to 50th in the world rankings following her victory at the HP Open in Osaka.

The 20-year-old became the first Briton in 24 years to win a WTA Tour singles title by beating Chang Kai-chen of Chinese Taipei on Sunday.

Watson rose 21 places from 71st as she moved back to British number one.

"I really wanted to do well this week so I could earn my rest next week because this is my last tournament of the year. I don't think I could have ended it any better," Watson told BBC Radio Five Live.

"Being in the top 50 was a real goal for me and it will push me to make harder goals for myself. I'm excited to have a break but I am looking forward to working hard again because it motivates me to achieve more.

"Laura and I have come through the rankings together, juniors and seniors - and we're both very competitive, so when we see the other doing well, it pushes us," Watson added.

"Knowing Laura did so well in China a few weeks ago definitely motivated me this week. But I think it's great we're really good friends off the court as well."

It was the first ATP Tour victory by a British woman since Sara Gomer won in California in 1988 and Watson was in no mood to downplay the achievement.

"I've been working to be more aggressive lately," she told BBC Radio Five Live. "When I got to the point when I was three match points down and she was serving for the match at 5-4 40-0 I just thought 'oh no, I had this, I was so close', but I just took it point by point, I don't know how I did it but I did.

"Now I've got the title and I am so happy, this ranks as one of the best days of my life.

"I've worked so hard for this moment my whole career. That's why I practised so hard, ran all those miles and lifted all those weights, for moments like this.

"I was in the changing room afterwards, changing my clothes, and I thought to myself, 'Did I really win?' So it's just starting to settle in."

Eighteen-time singles major winner Martina Navratilova paid tribute to Watson on Twitter, believing she was due some glory.

"Well done Heather- your determination, grit, talent and most of all hard work has finally paid off- congrats:)," she tweeted.

PA