WATCH: Carreno Busta apologizes for losing his mind

Now that's one way to make an exit. Pablo Carreno Busta lost his cool and the match to Kei Nishikori in the fourth round of the Australian Open, 6-7 (8), 4-6, 7-6 (4), 6-4, 7-6 (8).

The reason for his meltdown? The Spaniard was up 8-5 in the fifth-set deciding tiebreaker, playing for his first career quarterfinal in Melbourne. He had a somewhat open court for a passing shot, but his forehand clipped the net and landed right in front of Nishikori. Carreno Busta guessed left, but Nishikori nailed a winner to his right. The linesman called the Carreno Busta passing shot out—just a little late.

Instead of getting a replay when Hawk-Eye showed the Carreno Busta shot in, Nishikori was awarded the point. Carreno Busta didn't take this bad luck well—even though he guessed the wrong side of the court. He started arguing with umpire Thomas Sweeney, and the loss of concentration saw him lose the next three points and then match on a Nishikori ace.

"I don't need to watch the repeat, the replay of the point, because I know clearly that the line umpire calls out. Then Nishikori make a winner," Carreno Busta said. "Obviously, the point [is] for Nishikori was so we see. But sometimes the line umpires make mistakes, and that's the game, no?"

He was immediately apologetic for the way he exited Margaret Court Arena, which included throwing his bag and screaming toward the umpire as he stormed off.

"Obviously, I'm very sad, no, because after five hours fighting, after five hours' match, the way that I leave from the court wasn't correct, and I'm so sorry, because that's not [me]," the 27-year-old said. "But I think that the referee missed—and, well, I try to leave faster as possible when I lost that last point, because I know that in any moment I lost the head."

He issued another apology to his fans on Twitter (in Spanish) repeating roughly the same thing but adding, "I want to claim that Pablo Carreno is the one that has been on court for 5 hours and not the last 5 seconds."

It's a tough lesson, but one that Carreno Busta will learn from. Nishikori advances to a quarterfinal showdown with Novak Djokovic. At least Carreno Busta successfully defended his points from last year and will likely rise one spot to No. 22.

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