Chile's Marcelo Rios defied back pain that almost forced him to default, outlasting Andre Agassi over five sets to win the Grand Slam Cup and prize money of $1.3 million yesterday.

American teenager Venus Williams had to be content with $800,000, almost doubling her earnings for the year by beating Swiss Patty Schnyder in the women's final.

The towering 18-year-old outpowered her 19-year-old rival 6-2, 3-6, 6-2 as women appeared for the first time in the lucrative event for the best performers in the year's four grand slams.

Rios, the world number three, conceded he almost did not make it through after being kept on court for just under three hours before subduing Agassi 6-4, 2-6, 76, 5-7, 6-3 when the American double-faulted on the Chilean's second match point.

"My back started hurting yesterday (Saturday) and I thought about not playing," Rios, 22, said. "In the second set, I considered pulling out but then I saw that crowd. In that kind of match, you just can't quit."

Rios, who briefly held the number one spot after a brilliant start to the year in which he reached the Australian Open final, said he did not even know how much money he had won.

When somebody told him, he sounded pleased.

"That's a lot of money," he said. "But you know, I'm not the kind of guy who keeps buying cars and houses. I'll just put it in the bank."

Agassi, who had a frustrating grand slam season but received a wild card for the Munich event, appeared short of energy after Saturday's five-set semi-final thriller against Slovak Karol Kucera.

He won then after saving four match points but the effort appeared to exact a toll and he had to settle for the runner-up prize of $650,000.

"I definitely wasn't at my best physically but I was determined to get the job done," said the former world number one, who showed glimpses of his old form throughout the tournament. "I missed that little bit of strength but I still held up good."

Rios received treatment for back pain for several minutes after losing his serve to go 3-2 down in the first set.

He then broke Agassi to level the set, which he eventually won in 36 minutes on a forehand pass.

Agassi fought back in the second set, breaking his opponent immediately and again in the seventh game, when Rios hit a backhand long.

Both players held serve in a tense third set and a tie break was needed, which Rios took 7-1. The fourth set was also close and Rios dropped serve at the worst possible moment by netting a backhand.

The telling break in the decisive set came in the fifth game, in which Agassi hit a backhand wide to give Rios a 3-2 lead. The Chilean then stayed in command.

Rios was clearly hampered by his injury but still hit astonishing winners.

In the sixth game of the second set, he delighted the crowd when he slipped and fell, then fired a winning volley while sitting on the floor.

There was less drama in the women's final.

Williams, the world number five, relied on her trademark missiles to take the first set in 28 minutes with a big forehand volley.

Schnyder fought back in the second, running for every ball until Williams hit a straightforward backhand into the net to give her a 5-3 lead.

Serving for the set, the Swiss teenager had to save two set points before winning with another error by the sometimes clumsy Williams.

Schnyder, world-ranked ninth, had impressed in her semi-final here against compatriot Martina Hingis until the world number one pulled out because of cramp at 5-5 in the deciding set.

But there was little she could do to counter Williams, who was back in command in the deciding set, opening up a 3-1 lead and later sealing victory with a fiery two-handed backhand volley on her first match point.

"I really wanted this title," said Williams. I played pretty well in the first set, then she picked it up a bit in the second. I guess I just played that much better."

Grand Slam Cup Finals: Men: M Rios (Chile) bt A Agassi (US) 6-4 2-6 7-6 (7-1) 5-7 6-3.

Women: V Williams (US) bt Patty Schnyder (Swi) 6-2 3-6 6-2.

Jan Siemerink of the Netherlands won the £400,000 Toulouse Open tennis title by beating British top seed Greg Rusedski 6-4, 64 yesterday. Siemerink, the 20th-ranked second seed, outclassed Rusedski with fine returns and passing shots, breaking the 14thranked Briton twice to win in one hour two minutes.

It was the fourth tournament win of his career, and the second this year after his victory in the Rotterdam Open.