Nick Kyrgios has defied cramp to overcome three-time major winner Stan Wawrinka in three tough sets and reach the semi-finals of the Mexico Open in Acapulco.

In a marathon encounter lasting more than two-and-a-half hours, Kyrgios won 7-5 6-7 (3-7) 6-4, setting up a semi-final showdown against either fellow Australian John Millman or towering American John Isner.

It was a second-straight victory over a top-liner for Kyrgios, who had saved three match points before beating world No.2 Rafael Nadal in the previous round.

The Australian battled cramp during the closing stages of Thursday night’s match against Wawrinka, but hung tough to claim the win.

Earlier, fellow Australian Alex De Minaur lost 6-4 6-4 to German world No.3 Alexander Zverev.

Zverev’s semi-final opponent will be Britain’s Cameron Norrie, who beat American Mackenzie McDonald in the quarters.