And while the unassuming 27-year-old from King Williams Town in the Eastern Cape had his progress halted at this point by fourth-seeded Belgian Olivier Rochus, Klaasen also had the satisfaction of eliminating title-holder Rajeev Ram in a titanic battle in the previous round.
Klaasen trailed Ram 0-5 in the first set before staging a remarkable fightback in a game that lasted close to three hours - and going on to claim victory after a third-set tiebreaker.
What is more, reaching the quarter-finals is expected to move South Africa’s fourth-ranked Klaasen a substantial 100 places or so in the ATP world rankings from his present 417th mark.
And, in the process, Klaasen earned a tidy R100,000 in prize money — one of the biggest purses of his career.
“What is so admirable about Raven,” said South African Tennis Association CEO Ian Smith, “is that since he joined the professional circuit in 2002, he has never stopped trying to improve his game.
“And the fruit of his dedication is that he now playing possibly the best tennis of his career.”
With South African number one Kevin Anderson still perched on a fence of indecision as to whether to make himself available for the crucial World Group promotion tie against Germany in September, Klaasen will also come into the reckoning for one of the singles berths in the crunch September play-off along with Rik De Voest and Izak van der Merwe.
And ironically, it was with the help of a victory over Van der Merwe in the final qualifying round in the Hall of Fame tournament that Klaasen earned a place in the main draw.
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