Jenson Brooksby [left] and Casper Ruud

Casper Ruud was stunned by hard-hitting American Jenson Brooksby to leave the Australian Open draw without its top two men’s seeds after two rounds.

The Norwegian second seed, last year’s French and US Open runner-up, was chasing a first Grand Slam title and the chance to become world number one.

But the 24-year-old was outplayed by the world number 39 in a 6-3 7-5 6-7 (4-7) 6-2 defeat in the second round.

His exit follows injured top seed Rafael Nadal’s loss on Wednesday.

Brooksby, 22, took early control of the match with two breaks of serve in the opening set and he commanded play from the baseline in the second.

Ruud saved three match points in the third before winning a tie-break to force another set but Brooksby regrouped to break early in the fourth, sealing the win when his opponent sent a backhand long.

Brooksby will face Tommy Paul in the next round after his compatriot beat Spanish 30th seed Alejandro Davidovich Fokina in five sets.

The men’s draw was already without last year’s Wimbledon runner-up Nick Kyrgios, who withdrew before the tournament through injury, leaving Novak Djokovic as the overwhelming favourite for a record-extending 10th men’s title.

Meanwhile, Andy Murray produced another scarcely-believable display to fight back from two sets down to beat Thanasi Kokkinakis in an epic Australian Open match.

In one of the latest finishes in tennis history, Murray won 4-6 6-7 (4-7) 7-6 (7-5) 6-3 7-5 on a night of gruelling physical and mental endurance.

The match lasted five hours and 45 minutes, the longest in Murray’s eventful career.