Thanasi Kokkinakis' incredible four-year first at US Open

Thanasi Kokkinakis has dug deep at the US Open to post his first main-draw win at a grand slam event in more than four years.

The injury-plagued Australian overcame the disappointment of failing to serve out the first-round match in the third set to tough out a 6-3 7-6 (10-8) 6-7 (4-7) 6-2 victory over Ilya Ivashka on Tuesday.

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The 24-year-old Kokkinakis slugged it out with the Belarusian qualifier for almost four hours to earn a second-round shot at Rafael Nadal.

The emotional triumph, after a diabolical run with injuries, was his first main-draw win at a slam since an epic five-set comeback victory over compatriot Bernard Tomic at the 2015 French Open.

It was also Kokkinakis's first victory at Flushing Meadows, having lost a sapping five-setter to Janko Tipsarevic two years ago and being forced to retire with cramps in the deciding set against Richard Gasquet in 2015.

Kokkinakis appeared to be heading for a straight-sets victory after winning a pulsating second-set tiebreaker with a broken string.

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Desperate to finish the point quickly after snapping the string, Kokkinakis scrambled to the net and somehow won the rally with a forehand overhead, provoking rousing applause from the Court 6 crowd.

The world No.203 served for the match at 6-5 in the third set but couldn't buy a first serve when it mattered, then lost the breaker.

But he rebounded to break the Belarusian twice in the fourth set to prevail after three hours and 48 minutes of quality tennis.