MELBOURNE: Ivo Karlovic fired down 75 aces in a remarkable Australian Open first-round marathon against Argentina's Horacio Zeballos which lasted five hours 15 minutes and finished with a 6-7(6) 3-6 7-5 6-2 22-20 victory for the Croatian on Tuesday.

The tall 20th seed threw his hands in the air in delight after Zeballos ballooned an attempted lob high into the night sky to finally bring an end to the 157-minute fifth set.

Karlovic embraced his exhausted opponent then exchanged high fives with a large part of the crowd which had stuck with the contest from its start in the afternoon sun to the finish under the low wattage lights on the tiny Court 19.

With all the other matches on the outer courts long finished, a carnival atmosphere had developed as the two players tried and failed to break each other's serve in the final set.

Organisers sent ballboys running off to get more energy drinks as the marathon continued with the gloom punctuated occasionally by fireworks being set off at a match at the neighbouring Melbourne Cricket Ground (MCG).

Karlovic blasted 38 aces in the final set alone, while Zeballos chipped in with 33 in the match and 15 in the last stanza.

The break point Karlovic converted was only the fourth in the 42 games in the deciding set, with long rallies at a premium as the serves continued to thwack into the back fence at both ends.

Despite its length, the contest was still 38 minutes shy of the record for the longest match at the Australian Open - the 2012 final between Novak Djokovic and Rafa Nadal having gone five hours and 53 minutes.

Karlovic will have two days to rest his legs before his second round contest against local wildcard Andrew Whittingham, a serve volleyer who earlier beat Czech Adam Pavlasek 6-4 4-6 6-2 6-3 in a relatively modest 145 minutes.