After the game, several fans took to Marchessault's latest Instagram post - a photo of him and his wife - and left comments ridiculing the 29-year-old for diving during the loss.
"I was frustrated from the game, obviously, but also I get sensitive when people comment on family pictures," Marchessault said, according to The Athletic's Jesse Granger.
"It got the best of me, but there's no excuse. I sincerely apologize."
Marchessault responded to the criticism with comments such as, "Go suck on your mummy's t----- and stop wasting my time," according to ESPN's Greg Wyshynski.
The 5-foot-9 winger has contributed three goals and eight points over 10 playoff contests this summer.