Top-seeded David Nalbandian was knocked out by Austrian qualifier Daniel Koellerer 1-6, 6-3, 6-4 in the first round of the Mexican Open yesterday.
Nalbandian, last year's runner-up, appeared to be headed for a romp after winning the first set, but the Argentine's serve worsened and Koellerer wasable to take advantage to win only his sixth match ever on the main tour.
Koellerer broke early in the third set and clung to the advantage, saving break points at 3-2 and 4-3 against the Argentine for the biggest win of his career.
