Shanghai Masters: Nick Kyrgios retires after tie-break loss

Nick Kyrgios was booed off court at the Shanghai Masters after going through with a threat to quit his match if he lost the first-set tie-break.

The Australian lost the tie-break 7-5 to Steve Johnson soon after receiving a warning for smashing two balls out of court in frustration at a line call.

READ MORE: http://www.bbc.com/sport/tennis/41564893