Korolev benefits from Blake misfortune

Evgeny Korolev had cause for a double celebration but James Blake was left cursing his luck after the American fell foul of the ATP`s new round-robin system.

The top seed at the $416,000 Tennis Channel Open in Las Vegas, Blake was bumped from the quarter-finals on Friday when the ATP announced a mistake had been made in determining who should have advanced out of his round-robin group.

World number six Blake was incorrectly awarded the quarter-final berth by an improper ruling from ATP chairman and president Etienne de Villiers. Evgeny Korolev of Russia was subsequently given the spot and moved into his first career semi-final with a 6-4, 6-4 victory over American Sam Querrey.

According to the ATP, Blake was initially eliminated by the tournament tie-breaker rules.

The defending champion needed to complete Thursday's match against Argentina's Juan Martin del Potro in straight sets and lose five games or less.

Blake was leading 6-1, 3-1 when del Potro retired with a respiratory problem.

The relevant rule states than an incomplete match does not count as a match played for the retiring player.

That eliminated del Potro from the tie-breaker procedure with Blake and Korolev, who each finished with records of 1-1 in Group One.

Under ATP rules, Korolev should have advanced after beating Blake 6-2, 6-4 in the first round-robin encounter.

Otherwise, the tiebreaker would have been decided on total games won. That meant Blake could have gone through if he had completed his match against del Potro.