World No.2 Rafael Nadal withdrew from the Miami Masters tennis before his scheduled semi-final against Andy Murray on Friday with a knee injury, the ATP tour said via Twitter.

“Rafael Nadal has been forced to withdraw from today’s match at the SEOpen due to a knee injury,” a posting on the ATP’s Twitter feed said.

“Andy Murray advances to the final.”

Later on Friday, world No.1 Novak Djokovic was to face Juan Monaco for a place in the final.