LISBON There are those, former German champion Boris Becker included, who tend to believe that the end-of-season Masters Cup, with its 3.7 million dollars in prize money is just a glittering junket for an elite eight-man field, the trophy another bauble to add to the Christmas decorations.

But don't tell that to the likes of U.S. veteran Andre Agassi, or indeed Russian Marat Safin, who hopes to cement his position as world number one this week in Lisbon.

Becker, although he was happy to turn up for a share of the cake particularly as the season wrap-up was held throughout the 1990s in his homeland, felt the cash cow that the event has undoubtedly become was verging on the financially obscene.

However, Agassi, who after a glittering career could hardly be accused of being here for the money, insists the tournament is even harder to win than a Grand Slam and adds that the winner will certainly have earned his corn in the shape of a cheque for $1,520,000.

After beating Brazilian Gustavo Kuerten 4-6, 6-4, 6-3 in his opening round robin match on Tuesday, 1990 ATP Tour world championship winner Agassi said the very nature of the event made it a highly-intensive and gruelling affair.

"In many ways it's easier to win a Slam than it is this tournament because every match it's like you're starting the game in the fourth quarter," AFP quoted Agassi, the only man to win all four Slams on three different surfaces.

"I mean it's really high stakes. Guys know how to win in this tournament ... how to make you pay the price for mistakes.

"You've got to play well from start to finish. You also have to play back-to-back, so you're playing great players day after day.

"And that's harder physically and mentally than playing three-out-of-five and having a day to kind of regroup and get ready for your next one."

Agassi, beaten in last year's final in Hanover by old rival Pete Sampras, should know all about that forthcoming challenge he still has to face Olympic champion Yevgeny Kafelnikov of Russia and Swede Magnus Norman in his Green Group.

But in ousting Kuerten, plagued by hamstring trouble midway through their encounter, he showed he is moving back into the frame after missing the Paris Masters series with a hip flexor injury suffered three weeks ago in Lyon.

And if the Las Vegan can stack up four more wins by Sunday night he'll feel like a million dollars with 520,000 left over for good measure.