Arazi, ranked No 55 in the world, threatened to overrun the seventh-seeded Rios from the start, and produced the decisive shots after the Chilean had mounted a comeback from two sets down. Arazi prevailed, 6-2, 6-1, 5-7, 7-6. He then booked an appointment with a dentist.
Rios appeared to be in trouble even before the match began, calling the trainer to bind his right ankle as soon as he had completed the warm-up. He lacked his usual smooth movements and went for winners whenever possible rather than involve himself in lengthy rallies.
Arazi's reward is a meeting with Sergi Bruguera, the twice former champion, who defeated Michael Chang, the No 2 seed, 3-6, 6-4, 6-3, 6-4. Chang's elimination means that the Americans will not have a representative in the last eight of the men's event for the first time since 1969.
Bruguera was joined in the quarter-finals by a Spanish compatriot, Galo Blanco, a 20-year-old from Oviedo, ranked No 111. Blanco defeated Petr Korda, a former finalist, 1-6, 6-1, 7-5, 6-4, and now plays Australia's Patrick Rafter.
Rafter, overcame his compatriot Mark Woodforde, 6-2, 5-7, 6-1, 6-2, to gain the distinction of becoming the first Australian to reach the quarter- finals here since Peter McNamara in 1982.
Gustavo Kuerten, whose match against Andrei Medvedev was stopped overnight at 2-2 in the fifth set when darkness fell, defeated the Ukrainian on his fourth match point, 5-7, 6-1, 1-6, 6-1, 7-5.
Kuerten, who eliminated Thomas Muster, the 1995 champion in the third round, now plays Yevgeny Kafelnikov, the defending champion.
We trust that Kuerten does not turn up for the match in his underwear. Anything seems possible after the way the men's singles tournament has been stripped of seeds, although in Kuerten's case the problem lies in the colour of his tennis clothing, a mass of blue and yellow.
Christian Bimes, the President of the French Tennis Federation, has informed the Brazilian and his sponsor, Diadora, of his disapproval. "We don't want these guys going out looking like soccer players," he says.
The scenario is vaguely reminiscent of the fuss about Andre Agassi's "hot lava" dayglo outfit in 1990. Kuerten, however, is far too polite to call the President a "bozo", as Agassi did in the case of Bimes's predecessor, Philippe Chatrier.
But why would the 20-year-old Brazilian play in his underpants? "I have nothing white," he said. "They said here they don't mind if the players play in blue, yellow or green. I have a contract, and I have no more clothes to play in. I have nothing white. I have yellow socks, blue shoes. I can use the bandana in white. My underwear is white.''
Joking apart, the incident could lead to the French Fedderation finally adopting a dress code similar to Wimbledon's "almost entirely white."
There was an altercation in Bruguera's match against Chang after the American's brother/coach, Carl, became upset by the shouts of "Vamos!" by Bruguera's father/coach, Luis.
Carl Chang apparently said to Sergi Bruguera, "Don't look at your father all the time, he's coaching you.''
Luis Bruguera responded by turning to Carl and saying, "Silence, silence, shut up." And his son said to Carl Chang, "Are you silly?''
Surrey's Danny Sapsford upset the top seed, Doug Flach, the American who defeated Andre Agassi at Wimbledon last year, 6-3, 3-6, 7-5 in the final qualifying round of the Surrey grass-court championships in Surbiton yesterday.