"According to the sports scientists she is far too short to be a sprinter," says her coach, Ian Oliver. "But when she is in the water she seems to grow about six inches. Her stroke is so graceful, so effortless. A lot of swimmers, even the great ones, thrash about like piranhas. Sue's more like a porpoise."
It is four decades since a British woman won an Olympic swimming gold but there is an increasing conviction within the sport that the 21-year- old Rolph will end the drought and follow Anita Lonsbrough on to the winner's rostrum.
At the very least she is a serious contender for the 100m freestyle title which, like the corresponding athletics event, is regarded as the blue riband of the sport. In Istanbul four months ago she became the first Britain ever to win the European Championship over this distance - and again the first British gold medallist since Lonsbrough took the 200m breaststroke 37 years ago. This week Rolph is attempting to convert this success into another gold in the European short course championships in Lisbon. Although, as she says, this event, raced in a 25m rather than an Olympic-sized 50m pool, is not such a big deal, it is a useful tune- up for the national championships in Sheffield a week later, and invaluable preparation for Sydney.
Adrian Moorhouse, the last Briton to win any sort of Olympic title, in 1988, considers Rolph the best British female swimmer of the decade, and potentially the greatest of all time. Since her victory in Istanbul she has felt the full weight on shoulders finely sculptured by rigorous weight training. "I try not to think about it," she said during a break between sessions at the City pool near her Newcastle home. "But I can't avoid it. Sydney is always in my mind. Every time I go to the pool I stand on the edge and wonder what it is going to be like in Sydney. Everyone keeps telling me 'Don't worry, you'll swim really well' but every time I hear that my stomach just hits my throat."
In sport, such nervous tension is deemed to be beneficial, and there is certainly nothing in Rolph's sunny, outgoing demeanour which suggests that she is anything but confident in her burgeoning talent. She has beaten the world's No 1, Jenny Thompson, four times out of five over 50m and 100m in recent meetings, and although the American has recorded faster times, as Rolph points out, in the big races it is not breaking records but getting the final touch first that matters. "People remember winners, not records."
Rolph has known little but swimming all her born days. "I have devoted 21 years of my life to the sport," she says. "It consumes just about every waking hour." Waking time is 4.30am, 363 days of the year - she allows herself a lay-in at Christmas and New Year - and an hour later she is in the pool for two hours followed by a gymnasium session and more pool practice in the afternoon.
She sings to herself - usually pop songs she has heard on the car radio - to while away the tedious training hours but never gets bored. "Tired, yes, but never bored. I love swimming too much. Obviously there are times, usually just after I wake up on cold winter mornings when I ask myself 'Why the hell am I doing this?' But the truth is I love it. When you are training so much you live in your own world. Anything outside that bubble, I don't understand very much."
She is the original water baby and says her water-polo-playing father "must have thrown me in at the deep end the day I was born". She was swimming without armbands by the time she was two and at 13 she won eight gold medals at the national age group championships, though none of them were for freestyle, which she developed when she joined her coach, Oliver, at Newcastle the following year. At 14 Rolph was swimming faster times than Dawn Fraser at her best.
She swam in the Atlanta Olympics alongside - or rather behind, the now disgraced Michelle Smith, unsuspecting of the furore that was to follow. "I have to say I felt a bit sorry for her with all the innuendo that was flying around. I have always believed you are innocent until proved guilty. I actually got to talk to her at one stage and she seemed very nice. I was surprised when it all blew up the way it did, and the way the test was conducted seemed very bizarre, but in the end it has done neither Michelle nor swimming any good at all."
As European and double Commonwealth champion, Rolph no longer has to rely on financial support from her parents. She receives sufficient Lottery funding, as a world-class performer, to consider herself a full-time professional, driving a T-reg convertible and living comfortably with her Welsh fiance, Phil. "I doubt if even the Americans earn more than me."
She will go for gold in the 2002 Commonwealth games after Sydney when she will be 24, which used to be considered bus-pass age for swimmers. Nowadays they plough on until they are 30 or more. "But as far as the Olympics are concerned Sydney will be make or break for me. I don't know whether I will still be at my best by the time of the next Olympics in Athens. I will probably be retired by then. I want to make sure I get out at the right time, I don't want to be on the team as a tripper."
Except for Alan Shearer, Rolph's is probably the best-known face in Geordie sport. By rights it ought to figure prominently in this month's Sports Personality of the Year Awards, but, as she admits, swimming is not a high-profile sport. She will be doing her best to raise its profile in Lisbon and subsequently Sydney, where privately she reckons that only Thompson stands between her and gold. But she would prefer not to be the favourite. "I don't want to get to the Olympic final and having people looking at me and saying 'she is the one to beat'." It is inevitable, however, that such pressures will escalate.
Small fry she may be alongside some of the big barracudas of the pool, but it is comforting to know that Sue Rolph is unlikely to end up among the also-swams. There is a steely purpose about this porpoise.