Second seed and defending champon Novak Djokovic survived a thriller against Croatian veteran Ivan Ljubicic to reach the semifinal of the 2010 Barclays Tennis Championships.

Re-live the tense moments of Djokovic's marathon win, click here.

Djokovic made a bad start to the match and lost his serve twice to lose the opener by 6 games to 4. The second set saw Djokovic struggle even more in his service games which he somehow managed to hold and win the second set by breaking the Croat in the tenth game.

The decider turned out to be a lop-sided affair when Djokovic bagled the Croat to complete the 2-6, 6-4, 6-0 win in a match that stretched to almost two hours in play.

In the day's first quarterfinal, Austrian Jurgen Melzer caused a major upset when he beat the tall Croat Marin Cilic 7-6(8), 7-5 to reach the last four of the event.

Re-visit the entertaining moments of Melzer-Cilic clash, click here.

Melzer next faces Russian Mikhail Youzhny who humbled Andy Murray's conquerer Janko Tipsarevic 6-3, 6-4 in the day's second quarterfinal.