#1. Defeating Rafael Nadal in the fourth round of the 2014 Wimbledon Championships
The 2014 Wimbledon Championships was perhaps the tournament where Kyrgios first gained recognition. Kyrgios was given a wildcard to the main draw and boy did he make good use of that.
He defeated Frenchman Stephane Robert in the first round in four sets before creating a huge upset by ousting former semi-finalist Richard Gasquet despite dropping the first two sets. He then came from a set down to defeat Czech Jiri Vesely in four sets to set up a clash against second seed Rafael Nadal in the fourth round.The first set was pretty exciting as it went to a tie-break, but it was Kyrgios who took the set by winning 7-5. However, Nadal bounced back in the match to take the second set 7-5.
The third set went to another tie-break and Kyrgios took the lead in the match by taking the tie-break 7-5. Kyrgios totally outplayed Nadal by winning the fourth set 6-3 to reach his first Grand Slam quarter-final where he lost to Milos Raonic in four sets despite winning the first. Nevertheless, his victory over Nadal will definitely be the biggest one of his career as of now.