Rune unconventionally failed to shake the hand of the umpire after the match following an incident in the final tiebreaker which infuriated the Danish tennis star.
With Rune leading 2-1 in the tiebreak, the stadium lights were turned on during a point which clearly disturbed Rune and he ended up losing the point.
After losing the point Rune approached the referee to have the point replayed according to the rule of disturbing elements. The umpire disagreed with that, and he did not allow the point to be replayed.
The Dane ended up losing 7-5 in the decisive tiebreak, and after the defeat, Rune was very upset say the least.
"I am furious in some way. It is a completely brutal mistake by the ATP and the umpire out on the court. The light comes on in the middle of a point in the tiebreak in the third set, and the umpire does not stop the point", said Rune to TV 2 Sport after the defeat.
"We were clearly disturbed by it both of us. If he had lost the point, he would have complained. And I complain because I've lost the point. Its a big mistake that the tournament and those who control the light can even think of turning on the light in the middle of a point... it is the most unprofessional thing I have ever experienced in my life."
After the lost point, Rune explained his frustrations to the umpire, who watched the point on his screen to assess whether Rune had been disturbed by the light.
After the match, Rune was clearly still frustrated, and he did not want to shake the referee's hand.
"He doesn't deserve a handshake at all. I am never going to play with that referee again. He is usually very professional but this is one of the worst things I have experienced in my career.
It was Rune's first game game in Miami after he reached the final in the ATP Masters 1000 tournament in Indian Wells.