Dave Worsley: On Novak Djokovic retiring from the Australian Open Semi-Final - Sportstalk with D'Arcy Waldegrave

A shock withdrawal at the Australian Open for ten-time champion Novak Djokovic.

The Serb great sensationally withdrew after losing a marathon first set of his semifinal against second seed Alexander Zverev, in a tiebreak.

Meanwhile, the reigning men's champion faces a tricky match-up in his semifinal tonight.

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