Rising Cypriot Marcos Baghdatis delivered a major upset at the Australian Open on Sunday as he ousted the tournament's second-seed Andy Roddick to advance to his first career Grand Slam quarter-finals. The former world junior number one stunned Roddick 6-4, 1-6, 6-3, 6-4 to set up a quarterfinal clash with seventh-seeded Ivan Ljubicic who defeated tenth-seeded Thomas Johansson in straight sets. The 20-year-old Baghdatis secured a break in the first, third and fourth sets despite the American's overpowering serve and topped Roddick's 15 aces by one. "I think it's one of my best matches in my life," the 54th-ranked Baghdatis was quoted as saying by BBC Sport after the match. "I'm just in my own world and playing my best tennis and having the crowd here supporting me is great," added Baghdatis. Roddick, whose performance in the first three rounds made him one of the strong contenders for the title along-side Roger Federer, has not won a Grand Slam since his sole title at the 2003 US Open. "I didn't play that badly today," said the 23-year-old Roddick. "I think I would have beaten most people today but let's give credit where credit's due, he played a great match." "The shots he (Baghdatis) was able to come up with were very good," admitted the world number three. Meanwhile, fourth-seeded Masters Cup champion, David Nalbandian, booked himself a spot in the last-eight as he overcame 16th-seeded Spaniard, Tommy Robredo. Nalbandian next takes on French veteran, Fabrice Santoro or 11-seeded David Ferrer.