"Times are still extremely hard and difficult for all of us and I would never make a mockery out of these hard economic times by giving away a car," he said. "This has definitely been a lesson for me. In the future, I will be more responsible with what I choose to put on social media."
Pascal bet on the New England Patriots, but they went down to defeat when the New York Giants scored the winning touchdown in yesterday's football nailbiter.
The former light heavyweight champ's angst about the car, which is priced in the $100,000 range, is all laid out on his Twitter feed.
"Giving away my S550 ... I won't ever do that again," Pascal said of the high-end luxury car on Twitter.
"I need a ride back home," he tweeted in another post.
If that weren't enough, friends have posted video of him turning over the keys.
"Gimme the keys, gimme the keys," the unidentified new owner of the car cheerfully chants as Pascal slowly walks over and plops the keys to the sleek black sedan in his hands.
"Giants, baby, Giants," the man chants, pumping the air with his fists as a man laughs in the background.
Pascal holds his hands up in front of his face as the unidentified videographer turns his camera on him and says, "C'mon, champ, say bye-bye. Say bye-bye to the Benz."
The 59-second clip ends with the driver pulling into the street and yelling, "Thanks for the car!"
There's also a picture of Pascal grabbing his head and rocking back on the couch in disappointment as the Giants notched the win on TV.
His excitement during the game, which the Giants won 21-17, is clear in a stream of tweets, including exclamations like "Mon dieu mon dieu mon dieu (My God, my God, my God.)
The fighter takes a lot of good-natured teasing from his friends, including one who tells him to look at the bright side because fellow Haitian Jason-Pierre Paul won a ring with the Giants. Olympic gold medalist Bruny Surin also quipped that if Pascal wanted to go car shopping, he'd keep him company.
There was one other, considerable bright note for Pascal: "At least I still have my Range Rover," he said.