Paris - Serbia's Novak Djokovic on Wednesday crashed out of the Paris Masters in his first match, losing 0-6, 7-6 (7/5), 6-4 to American journeyman Sam Querrey in the second round.
Djokovic, who is assured of finishing as the top of the ATP world rankings at the end of the season, has not lost a match at such an early stage of a competition since Miami in March 2010.
His departure is a fresh blow for the tournament which has already had to do without star draw absentees Roger Federer and Rafael Nadal.
Djokovic, who regardless of this defeat takes over the world No 1 spot from Federer on Monday, strode onto the court wearing a Darth Vader mask but found himself the victim of a Halloween horror show.
Querrey fired 18 aces in a battle lasting just over two hours, with the American winning his first career match against a top three player after nine defeats.
Djokovic had said this week the lack of a rest week prior to the season-ending World Tour Finals which begin in London on Monday could have repercussions, though barely imagining that he could be the week's first major victim.
The Serb had said he was trying to conserve his strength for the final competitive sprint - even in a season shortened by a fortnight.
"It is a big challenge," he told a news conference in the French capital.
"Obviously I'm sure all the participants in London will agree that this (ending the pre-London preparation week) is definitely not something that goes in the favour of us preparing for the most important event in the end of the year."
Wednesday's shock win was the first for the 23rd-ranked Querrey against Djokovic.
Djokovic, who had not played since beating Andy Murray for the Shanghai title to win two Asian trophies in subsequent weeks last month, found his win streak stopped on ten.
The last two places in the London field will be decided this week in Paris, with Jo-Wilfried Tsonga the next qualification candidate.
He heads Serb Janko Tipsarevic, who kept his hopes alive as he reached the third round at the Bercy arena of Dutchman Igor Sijsling 6-4, 7-6 (7/0).
French 12th seed Richard Gasquet lost his chance to continue on pace for the year-end event as he went down in the second round Dutchman Igor Sijsling 7-6 (7/5), 4-6, 6-1.
Provisional London 12th man Juan Monaco of Argentina bolstered his long-odds hopes with a 7-6 (7/4), 6-2 defeat of Bulgarian Grigor Dimitrov.
Results from the third day of the Paris Masters on Wednesday (x denotes seeding):
Andy Murray (GBR x3) bt Paul-Henri Mathieu (FRA) 7-5, 6-3
Juan Martin Del Potro (ARG x7) bt Alejandro Falla (COL) 6-2, 6-2
Michael Llodra (FRA) bt John Isner (USA x10) 6-4, 7-6 (7/5)
Nicolas Almagro (ESP x11) bt Albert Ramos (ESP) 7-6 (7/1), 6-7 (4/7), 6-3
Gilles Simon (FRA) bt Victor Hanescu (ROM) 7-5, 6-3
Janko Tipsarevic (SRB x8) bt Igor Sijsling (NED) 6-4, 7-6 (7/0)
David Ferrer (ESP x4) bt Marcel Granollers (ESP) 6-1, 6-3
Juan Monaco (ARG x9) bt Grigor Dimitrov (BUL) 7-6 (7/4), 6-2
Kevin Anderson (RSA) bt Richard Gasquet (FRA x12) 7-6 (7/5), 4-6, 6-1
Sam Querrey (USA) bt Novak Djokovic (SRB x2) 0-6, 7-6 (7/5), 6-4