The British number one is guaranteed £53,125 just for turning up in Germany, but there is plenty more on offer if he can produce the form which earned him a place in the elite eight-man field.

Henman could pocket £918, 750 if he wins the tournament without a single defeat, but more importantly, it would see him rise six places to third in the world ranking list.

Davis Cup teammate Greg Rusedski is on stand-by to make a late entry into the event after Andre Agassi strained his back while practising with Alex Corretja on Tuesday.

Tough draw for Henman

Henman: Aiming to make a big impact

Henman was drawn in the same round robin group as Rios, Agassi and Corretja and will face the Chilean left-hander on Tuesday night.

"My aim this year was originally to make the top 10. Well I did that and now I would like to make the top five and possibly higher.

"If I'm playing at my best I know I have a chance against any player in the field. It will be up to me to prove it," he said.

Henman has never beaten Rios or Corretja but has a victory over Agassi to his credit - although the American's injury throws up the prospect of an intriguing all-British battle.

"I don't wish an injury on anyone but judging by what happened to Andre today, I may not be on stand-by for too long. To be honest, I'm hoping to get some matches," said Rusedski.

Tournament officials agreed to delay Agassi's match with Corretja until Wednesday, but he is still unable to stand up straight despite treatment from a physio.

Pete Sampras heads the other group, which is completed by Carlos Moya, Karol Kucera and Yevgeny Kafelnikov.

Sampras is bidding to set a new record of finishing six successive years as world number one, but goes into the event with a slender 33-point lead over Chilean Rios.

Tuesday schedule (play starts 1.00pm GMT): P Sampras v Y Kafelnikov; C Moya v K Kucera. (Not before 6.30pm GMT) M Rios v T Henman.

RED GROUP

Pete Sampras (USA) Age: 27; 4 tournament wins this year including Wimbledon; 1998 win-loss record 58-16.

Carlos Moya (Spain) Age: 22; 2 tournament wins this year including French Open; 1998 win-loss record 46-26.

Karol Kucera (Slovakia) Age: 24; 2 tournament wins this year; 1998 win-loss record 53-26.

Yevgeny Kafelnikov (Russia) Age: 24; 3 tournament wins this year; 1998 win-loss record 56-27.

WHITE GROUP

Marcelo Rios (Chile) Age: 22; 7 tournament wins this year; 1998 win-loss record 68-16.

Andre Agassi (USA) Age: 28; 5 tournament wins this year; 1998 win-loss record 68-17.

Alex Corretja (Spain) Age: 24; 4 tournament wins this year; 1998 win-loss record 52-20.