The Australian star beat home favorite Paul Jubb 3-6 6-1 7-5 6-7 (3-7) 7-5 in an exciting matchup but felt one of the fans overstepped the line in his cheers.
Having won the match point, Kyrgios turned to one of the stands and, spitting on the floor, went to the net.
Asked by a reporter if he really spat at this fan, Kyrgios replied: “Yes, one of those who disrespect me. I wouldn’t do that to someone who supports me.
“I’m fine getting a lot [heckling]. What I don’t understand is that as soon as I gave it away, for example, in Stuttgart, I gave it away and got a penalty.
“As soon as I won the match, I turned to him. I’ve dealt with hate and negativity for a long time, so I don’t feel like I owe this person anything.
“He literally came to the match just to not really support anyone. Rather, to stir up and show disrespect.
Earlier this month, Kyrgios said he was subjected to racist abuse from the crowd at a tournament in Stuttgart, whose organizers said they were investigating.
The Australian said he had not been subjected to racist abuse on Tuesday, but was concerned about the frequency of abuse from fans.
“I’m just starting to think it’s okay, when it’s actually not,” he told reporters. “I didn’t say anything to the crowd until they started, just every time I went down the far end. I don’t know if this is normal or not.
“This has nothing to do with Wimbledon. I just think that a whole generation of people, like on social media, think they have the right to comment on every negative thing. It just goes on in real life.
“Because there’s a fence and I can’t physically do or say anything because I’m going to be in trouble, so they just feel like they can just say whatever they want.”
This was not the only controversial moment in the match, as Kyrgios was also unhappy that the line judge recorded a point in the first set.
He later said during his press conference that Wimbledon umpires should be younger than “actually young people have better eyesight”.
Krygios will play doubles against Thanasi Kokkinakis on Wednesday and continue his singles campaign on Thursday against 26th-placed Filip Krajinovic.