HEATHER WATSON defeated number two seed Melanie South in straight sets at the AEGON Pro-Series Barnstaple.

Laura Robson, the other big hope for British women's tennis, had succumbed to the power of Naomi Cavaday on Centre Court.

But in the next match, Watson used her wide range of shots to overcome South's power game.

The 17-year-old showed she had brought her US Open junior title-winning form to North Devon by reeling off four straight games to clinch a 7-6, 6-2 victory.

"I'm really happy with that, I played well," said Watson.

"After the US Open, it's nice to get some wins over here as well.

"I had an upset two weeks ago against the number two seed (losing to Valerie Tetreault at Saguenay in Canada), but I was able to beat the number two seed this week."

In a first set that extended well over an hour, South at times appeared to have too much power for Watson.

But the teenager from Guernsey showed off her variety of shot to a large crowd featuring plenty of schoolchildren.

"I haven't played someone with that much pace in the juniors," said Watson. "She has a very hard first serve that I was struggling to return.

"I had to work really hard, so I wasn't able to be that aggressive, I was more defensive.

"I want to be more the person on the offence than the defence. But some people have compared my game to Martina Hingis, where I use my opponent's pace and power."

If Watson achieves half of what Hingis managed in her short career, she will do well. For the time being she is just pleased to be into a second-round meeting with another rising star — French Open junior champion Kristina Mladenovic.

"I've got a tough next round against the junior Roland Garros winner," added Watson. "We've played each other twice and it's 1-1 at the moment.

"She is another hard-hitter with a big serve."

Watson won the first-set tie-break 10-8 with South netting a backhand and then virtually destroying the scoreboard with a wayward forehand.

The second set was brisk in comparison.

The first four games went with serve, but after holding for 2-2, South called the trainer, complaining of discomfort in her left hip.

Despite the medical work, the British number four's movement was clearly restricted, making Watson's backhands unreachable.

South was an increasingly frustrated figure as Watson won four games in a row, taking the match with an ace.

Robson lost the first set against big-hitting British number five Cavaday 6-2.

The 15-year-old forced a tie-break in the second set but Cavaday raced into a 5-0 lead.

At 6-1, she had five match points. Robson saved the first with backhand pass, but put another backhand wide on the next point to concede the match.

"I thought my performance was good," said Robson. "It could have been better on how many mistakes I made, but I thought it was a solid match and I played pretty well.

"She hits really hard, no one I have played in the juniors hits the ball as hard as that. And it's quite an awkward shot to return because I'm not used to playing left-handers — it spins the other away and I got jammed up sometimes."

Robson had the Tarka fans on her side, making the victory even more satisfying for Cavaday.

"I was nervous before the match but that wasn't because she was young or British, it was because she is a tough player," she said.

"It's a little strange to be playing in my home country and having the crowd cheering for my opponent. But I think I won them over in the end."

Cavaday will be the underdog today when she takes on top seed Ksenia Pervak of Russia in the first match on Centre Court.

"I'm really looking forward to my next match," added Cavaday. "I have some things I want to work on. It was a good performance today but I know I will have to play better than that tomorrow."

Four British players are through to today's second round: Cavaday, Watson, Lisa Whybourn and Cornwall's Jade Curtis.

Anna Smith, Nicola George and Helen Parish bowed out in first-round matches yesterday.

She may be out of the singles, but Robson's involvement at Tarka is not all over just yet.

She will team up with Watson in the doubles against number two seeds South and Sarah Borwell — South's injury permitting.

"I'm really looking forward to playing with Heather, I've never played with her before," said Robson. "But it will be a tough match against Mel and Sarah."

Play is due to start today at 11am with Robson and Watson's doubles match on Centre Court at 5.30pm.

Ticket details are available from the tournament website.

Check back on www.thisisnorthdevon.co.uk/proseriestennis later for reports on the action.