British number two Greg Rusedski was edged out of the first round of the Madrid Masters Series 7-6 6-7 6-7 by big-hitting Croatian Ivo Karlovic.
The closely-fought tie went to three tie-breaks as both players held serve before Karlovic emerged the winner.
Rusedski, 32, clinched the first set with an ace in a nail-biting 7-5 tie-break but the Croatian battled back to win the next two 7-2 and 7-3.
Karlovic will now face American star Andy Roddick in the second round.
Rusedski admitted afterwards that he always thought his Croatian opponent was going to be tough.
"If you could've written the worst draw for me then this was it," he said.
"With the altitude here and the hard courts his serve was even faster than usual and it's not fun for anyone to play him.
"I didn't do much wrong and did not lose my serve but he played some really good tennis."
There was not a single break point opportunity in a first set predictably dominated by powerful serving, with Rusedski gaining the crucial advantage in the tie-break following Karlovic's first double fault.
Karlovic, who won four points more than Rusedski in the opening set despite losing it, levelled when the Briton put a backhand volley into the net in the next tie-break.
The third set began very differently to the previous two, Rusedski saving three break points in the opening game and then being denied two of his own in the next.
He grew increasingly frustrated, both by line calls and his inability to finish off his 6ft 10in opponent, and his misery was compounded when he left a Karlovic backhand that was correctly deemed to have clipped the line in the deciding tie-break.
Rusedski, who served 10 double faults, twice as many as Karlovic, finally succumbed in two hours 17 minutes to the Croat's 24th ace.
Meanwhile US Open semi-finalist Robby Ginepri ousted the final remaining Frenchman in the tournament, defeating Sebastien Grosjean 4-6 6-4 6-4 in round two.
The 16th seed has reached at least the quarter-finals of his last four events and hit back against Grosjean, who had won their previous three meetings.
Fifth seed David Nalbandian moved into round three with a comfortable 7-6 6-3 win over Jurgen Melzer, while 11th seed David Ferrer survived a second-set wobble to defeat Agustin Calleri 6-3 4-6 6-4 and Fernando Gonzalez of Chile beat Spaniard Fernando Verdasco 6-3 1-6 6-3.
Max Mirnyi of Belarus overpowered Spain's Juan Carlos Ferrero to set up a second-round match against Mariano Puerta.
And in the remaining first-round encounters, French teenager Gael Monfils was beaten in straight sets by Belgian Christophe Rochus, Spain's Carlos Moya beat Filippo Volandri of Italy 6-1 6-2 and Jose Acasuso of Argentina advanced when Russia's Mikhail Youzhny retired hurt.