World No.1 Novak Djokovic’s hopes of preparing for another grand slam bid with the 49th title of his career were dashed by giant Croatian Ivo Karlovic at a windswept Qatar Open on Thursday.

The towering 35-year-old Karlovic, the tallest and oldest player on the main tour, won 6-7 (2-7) 7-6 (8-6) 6-4 to make the semi-finals.

Seven-time grand slam champion Djokovic often appeared affected by the conditions, especially with his groundstrokes, but that did not prevent Karlovic hammering down another 21 aces, making 67 for the tournament so far.

That took him to within 12 of Andy Roddick’s 9074 aces, the second highest ever.

Djokovic was sufficiently exasperated to fling down his racquet in the second set and to sling it along the floor in the third, eventually settling for a smile and congratulations to Karlovic.

“I can’t say if it was surprising or not, but he served very well,” Djokovic said.

“But you could expect that. I was coming into the match knowing that I will have very, very few chances. I was hoping that these conditions and the wind would kind of give me some second serve opportunities, but it didn’t look this way.”

Djokovic feels he still has a decent chance of winning the Australian Open for the fourth time in five years, especially as a doubles loss to Rafael Nadal later in the day left him free to fly to Melbourne earlier than expected.

The 14-times grand slam winner from Spain had himself suffered a stunning singles loss, in the first round, and afterwards made sympathetic noises.

“I don’t feel better because Novak lost,” Nadal said. “It’s not going to make me play better tomorrow.

“It’s the first tournament of the year and we both came here to do well, but that was not the case. Ivo played unbelievable in the last set.”

Karlovic will now try to reach the 13th final of his long career when he takes on David Ferrer, the fourth-seeded Spaniard, in the semi-finals, feeling that he is fitter and more confident than for several years.

The tournament favourite is now Tomas Berdych, the former Wimbledon finalist, who outplayed a disappointing Richard Gasquet, the 2013 champion from France, by 6-2 6-1.

“The conditions were not easy, but my plan to deal with the match worked well,” said the third-seeded Czech who faces Italy’s Andreas Seppi on Friday.

Seppi defeated Croatia’s Ivan Dodig 7-5, 6-4 in his quarter-final.