Barry Humphries, aka Dame Edna, once referred to Australia as: "Koala Triangle, a mysterious zone in the southern hemisphere where persons of talent disappear without trace." Pete Sampras would not disagree.

The last of the men's quarter-finals were played yesterday against the backdrop of his shock departure, with both Chile's Marcello Rios and Nicholas Escude of France reaching their first Grand Slam semis.

Sampras won here last year and at Wimbledon, thus partly preserving a sustained belief in the status quo. But all about him was turmoil, accentuated when he lost early at Roland Garros and Flushing Meadow.

Currently Grand Slam seedings in the men's game, based on computer rankings, count for almost nothing, with anybody in the top 100, or even lower, likely to beat anyone in the top 20.

Theoretically this should make for extremely exciting tournaments, but because the ATP Tour is generally so poor at projecting its players, the public are understandably finding matters a little bewildering.

They had just, albeit somewhat reluctantly, managed to get their heads and tongues around the name of Alberto Berasategui when the Spaniard lost his quarter-final against Rios.

A nation had mourned when Berasategui knocked out their own Pat Rafter, the number two seed, in the third round, and then watched in amazement as the little Spaniard with the most peculiar grip put paid to Andre Agassi's burgeoning comeback.

Berasategui's hold on his racket means he uses the same side of the strings on both the forehand and backhand. This seems to defy both good sense and the laws of physics, to say nothing of medical advice.

The Spaniard appears likely to snap his wrist with every shot, but it works and he duly took the first set against the pony-tailed Rios, whose own left-handed game is far from orthodox.

The 22-year-old Rios, the number nine seed, has been edging closer and closer to Grand Slam success. Last year he reached the quarter-finals here and at the US Open, and the last 16 at Roland Garros and Wimbledon.

The Chilean, who has had a small knot of highly vocal supporters at all his matches, is rather easier on the eye than he is on the ear, and should he rise to the very top, the authorities may have to persuade him to enrol at a charm school.

For the time being, Rios lets his racket do the talking, and very sweet it is. He never appears the least hurried, gliding around court on super fast feet to hit ground strokes of magnificent depth and acute angle.

Berasategui, despite taking that first set, was clearly physically fragile after his previous two epics; Rios steadily increased the pressure and won comfortably 67, 6-4, 6-4, 6-0. The Spaniard, who must have run at least a marathon in the previous rounds, could barely stand in the final few games.

The other quarter-final between Escude and Nicholas Kiefer, Boris Becker's protege, saw the 20-yearold Kiefer, a quarter-finalist at Wimbledon last year at the first attempt, cruise into a two-set lead against the 21-year-old Frenchman who at the end of 1996 was ranked at 406. He is currently ranked 81 against Kiefer at 29.

Both were highly talented juniors, with Escude's progress being hampered by a serious back injury. But his form, and particularly his world-class backhand, has been the revelation of the Open.

Kiefer learned one of the great lessons of tennis, or any other sport, in this rain-interrupted five setter: never let up until the match is over.

At 4-4 in the third set, the German lost his concentration and Escude - nicknamed the "second Scud" - was through him before he could blink. On a decidedly cool evening the young Frenchman was suddenly blowing super hot, and levelled.

The roof was closed midway through the final set, in which there was a long delay, but the Frenchman maintained his wonderful comeback of which he is making a habit.

Kiefer was left to rue his mind slip, although he is undoubtedly a name for the future. Escude is a name for now, and will play Rios tomorrow for a place in the final.