Pablo Carreno Busta comes across as a calm and cool player. But at the 2019 US Open, he lost his cool after losing his 4th round match against Kei Nishikori in a 5th set tiebreak, 76(8), 64, 67(4), 46, 67(8).
Busta had an argument with a chair umpire over a challenge in the fifth set tiebreak, which he went on to lose.
Busta had a warm exchange with Nishikori at the end of the match but lost his composure shortly thereafter. He threw his bags on the court and yelled in anger.
To be fair to PCB, he apologized for his behavior when he met with the press.
Nishikori retired during his next round match against Novak Djokovic.