Kyrgios said his elbow injury -- and Murray 's ability to absorb pace and dispense variety -- were too much to overcome .
Kyrgios upset Rafael Nadal en route to the 2014 Wimbledon quarterfinals .
Kyrgios , who upset Rafael Nadal en route to the 2014 Wimbledon quarterfinals , said his elbow injury -- and Murray 's ability to absorb pace and dispense variety -- were too much to overcome .