'Cotton Eye Joe' Blasts Through Stadium During Montreal Tennis Match

A nail-biting tiebreaker at a professional tennis tournament was interrupted thanks to "Cotton Eye Joe!"

The match was as close as it gets at the semifinals of Montreal's National Bank Open ... Jessica Pegula and Iga Swiatek were trading points, with Pegula ahead 4-3 in the tiebreaker.

As the ball was in play, everyone in the venue heard "If it hadn't been for the Cotton Eye Joe" blaring from the speakers ... the chair ump immediately suspended play.

You hear the announcer kinda shocked, but musically knowledgeable, telling the audience, "Oh wow, 'Cotton Eye Joe' just came on mid-rally."

The point was replayed and in the end, the interruption may have changed the momentum, because Pegula never scored another point and Swiatek won 7-4, taking the second set.

Fear not, Pegula fans ... she won the match in the third set.