Andy Murray wasn't maybe totally satisfied by his haircut or more probably some of his front hairs were disturbing him. He made a little on-court adjustment to it during his match against Rafael Nadal in London (ATP Finals 2015, Masters).

SQUIRREL RUNS ONTO COURT AND INTERRUPTS MATCH at 2015 US open

An Iguana stopping the match between Tommy Haas and Jiri Vesely at the Miami Open.

Novak Djokovic win the 3rd set against Stan Wawrinka but stay on his side of the court. Why ? He simply didn't realized that the set was already finished.

Federer's Dad defeats Roger