Third seed Argentine David Nalbandian went out of the Toronto Masters in the first round when he was beaten 6-1, 6-2 by gray-haired Italian Davide Sanguinetti.
The burly Nalbandian was completely outclassed by the 33-year-old qualifier, who needed just 58 minutes to collect his first win in three attempts on Canadian hard courts on Monday.
In other first-round action, fourth seed Ivan Ljubicic of Croatia eased passed Spain's Nicolas Almagro 7-5, 6-1 and fifth seed James Blake needed just 56 minutes to crush the hopes of home town favourite 17-year-old Canadian Philip Bester 6-4, 6-1.
In contrast, Argentina's Jose Acasuso needed more than two hours and an epic second set tie-break to beat Germany's Bjorn Phau 7-5, 7-6 (20-18).
The tie-break equalled the longest on the ATP Tour record books. It marks the fifth time a singles tie-break had gone the record distance first reached by Bjorn Borg and Premjit Nall at Wimbledon in 1973.
Sanguinetti had just three career wins over top 10 opponents and the 24-year-old Nalbandian -- currently a career-high number three in the world rankings -- represents the biggest scalp claimed by a man who spent last week playing at a Challenger event in Recanati, Italy.
"I was relaxed," the 68th-ranked Sanguinetti told reporters. "If I lose, it's not a shame to lose to number three in the world. I was surprised by the score but I think I made him play my game.
"I love it. I love to see the old man can still win against the young guys."
The Argentine attributed his early exit to a fever that he said left him short of energy.
"I had a fever but I wanted to try and play," said the South American. "I said to myself that I would give it a go."
"I tried to compete but I didn't have the energy today."
Czech Tomas Berdych, seeded 13, advanced with a 6-4 7-5 win over Canada's Daniel Nestor while 15th seed Fernando Gonzalez of Chile scraped by Sweden's Robin Soderline 6-3 4-6 6-2.
Ninth seed and Australian Open finalist Marcos Baghdatis joined Nalbandian at the exit after falling 5-7 6-2 6-3 Julien Benneteau of France.
Britain's Tim Henman received easy passage into the second round breezing past Sweden's Jonas Bjorkman 6-2 6-3.
Henman's former Davis Cup team mate Greg Rusedski, however, lost 6-4 6-2 to Russian Mikhail Youzhny.
In a battle of former French Open champions, Spain's Carlos Moya brushed past Argentina's Gaston Gaudio 6-1 6-4.
The tournament moves into top gear on Tuesday when world number one Roger Federer and French Open champion Rafael Nadal return to action for the first time since the Wimbledon final.
Federer will open his account against Frenchman Paul-Henri Mathieu while Nadal takes on Chile's Nicolas Massau.