Andy Murray strode through to the semi-finals at the Sydney Classic after opponent David Goffin was forced to retire with an injury.

Murray won the opening set 6-2 before eighth seed Goffin, who had been receiving treatment on his knee, determined he could no longer continue.

It is the first time the 34-year-old Murray has reached a semi-final on the ATP Tour since winning the European Open title in October 2019.

Though not ideal circumstances, Murray will at least be glad of the extra rest after his three-hour encounter with world number 23 Nikoloz Basilashvili in the second round. The Scot has also been drawn to play Basilashvili in the first round of the Australian Open.

Murray will face Reilly Opelka in the last four in Sydney after the American beat compatriot Brandon Nakashima 7-6 (7-4) 6-2 to advance.

Top seed Aslan Karatsev was made to work for his win against Italy's Lorenzo Sonego but secured a 6-3 3-6 6-2 victory to book his semi-final place against Briton Dan Evans, who defeated American Maxime Cressy 6-4 7-6 (7-5). Cressy reached the final of the Melbourne Summer Set tournament last week.

At the Adelaide International 2 event, third seed Karen Khachanov tumbled out after losing in straight sets to Arthur Rinderknech, the Frenchman coming through a 7-6 (9-7) 7-5 winner.

Rinderknech will face compatriot Corentin Moutet in the semi-finals after the qualifier overcame Thiago Monteiro 6-4 6-4.

Fourth seed Marin Cilic battled to beat American Tommy Paul 6-4 2-6 6-3, and a test awaits against Thanasi Kokkinakis who defeated fellow Australian Aleksandar Vukic 6-7 (5-7) 6-3 6-2.