Ernests Gulbis has been knocked out of the Australian Open at the first-round stage following a dramatic five-set defeat at the hands of Thanasi Kokkinakis in a mammoth battle at Melbourne Park.

The 11th seed looked on top and had four match points to progress through, but it was to be the underdog, ranked at 147th in the world, who claimed a 5-7 6-0 1-6 7-6(2) 8-6 win to advance into the last 64.

Despite losing his serve in the second game, Gulbis managed to battle through to see out what was a tight opener in front of a packed crowd, which proved to set the tone for the remainder of a match which stretched over four hours.

Far from being disheartened by the early setback, Kokkinakis regrouped and claimed a whitewash victory in the second set, winning three breaks of serve to brush aside Gulbis.

The Latvian managed to take a potentially pivotal third set, however, capitalising on four losses of service game from his opponent to take control of proceedings.

It looked to be all over for the Australian wildcard, although having incredibly survived four match points he managed to take the set to a tie break, where he held his serve to prevail 7-2.

That provided a thrilling decider which took the clash into its fourth and final hour, and much like the contest as a whole the set remained tight throughout.

Both players held their serve right up until the 14th game, when Kokkinakis was able to hold his nerve to edge out his more illustrious opponent and claim a dramatic upset on home turf before receiving a standing ovation from the Margaret Court crowd.