The French Open dream of underdog Australian wildcard Jordan Thompson has ended in heartache following a four-and-a-half hour marathon defeat at the hands of Croatian monster Ivo Karlovic.

The impressive 22-year-old was outlasted in a five-set epic by the 37-year-old 27th seed 6-7 (2-7) 6-3 7-6 (7-3) 6-7 (4-7) 12-10 in 4 hours and 31 minutes.

The loss ensures Thompson falls short of the best wildcard effort by an Australian at Roland Garros – Thanasi Kokkinakis’ third-round defeat to Novak Djokovic last year.

But he will leave Paris with a record payday of 60,000 euros ($A93,000), a career-high ranking, currently 87, and a legion of new fans.

Thompson sniffed an upset when he took the opening set in a tiebreak, but was forced into a scrap once the 211cm Karlovic began to find rhythm with his serve soon after.

After hitting 57 per cent of his first serves midway through the first set, Karlovic became progressively more proficient as the match went on – serving at 64 per cent in the second and 69 in the third.

It made all the difference – Karlovic won 83 per cent of points when his first serve found its mark.

And the veteran Croat routinely went to the most dangerous weapon in his arsenal to get out of trouble against the 22-year-old Australian, who earned 10 break points but was able to convert just one.

In all, Karlovic sent down a tournament-high 41 aces and his rocket serves were coming down at an average of 202km/h – by contrast, Thompson’s fastest hit 205km/h.

Thompson blew several opportunities late in the fourth set, going from 30-0 up serving for the set at 5-4 to a tiebreak in a matter of minutes.

But he recovered to take the tiebreak 7-4 – closing it out with a rare pair of aces – and force a decider.

Having been forced to handle Karlovic’s powerful serve all match, Thompson began to exact revenge late on – crucially six of his 12 aces came in the fifth set.

Thompson incredibly saved triple break point in the 15th game of the fifth set to hold serve – where a break would’ve allowed Karlovic to serve for the match.

It proved to no avail, however, as Karlovic eventually broke him with a deep backhand winner in the 21st set and all Thompson could do was stare at the sky before Karlovic sent down three aces to serve out the match.