The match was between Canadian player Katherine Sebov (white shorts) and American Alycia Parks (pink shorts) in the round of 16 of the ITF W60 tournament in Las Vegas.

Sebov won the match in straight sets, but things got physical after Parks claims Sebov squeezed her hand too hard at the net following the match ... and made it clear she didn't like it one bit.

Parks -- who was already heated and had thrown her racket after the final point -- went after Sebov following the shake and that's when all hell broke loose ... with the 2 players shoving each other!!!

The line judge had to interfere ... and Parks' dad jumped a fence (hilarious BTW) to get on the court to help break it up.

Things finally cooled down ... and Parks addressed it with reporters after the match, saying, "She squeezed my hand very hard."

Another pro, Sachia Vickery, also backed Parks' claim, saying, "I was there she def squeezed her hand at the net. I hope they don’t try to spin this."

"The ref clearly says he saw it . Won’t be shocked if nothing is done about it tho"