The French pro played an incredible 62 $6.50 PokerStars SNGs in sixty minutes, playing on four-monitors on the final table set with his every move broadcast to an enthusiastic audience.
ElkY needed to turn a profit to clinch the record, and needed to cash in the final tournament to finish in the black.
He would do better than cash, defeating player "King Sampie" in a spirited heads-up battle to claim the game and the record with a $23.67 profit.
"I'm tired, actually," Grospellier told PokerListings.com. "It was pretty exhausting because I was really not prepared.
"I arrived from Las Vegas yesterday and expected to have a little more time to prepare."
Grospellier began the challenge confident in his abilities, loading as many as 40 tournaments at a time before the pace began to catch up with him.
"It was out of control," he said. "Shorthanded play went so fast and I was sitting out a lot, but at the end I managed to regain momentum and got better."
He told PokerListings he was surprised to turn a profit at all.
"I thought I was down a lot, actually," he said. "I felt like I kept losing and sitting out of the early games."
Khan, who gained internet notoriety when he videotaped himself playing 26 SNGs at one time, was one of many Team PokerStars Pro pros who hung around to sweat their teammate.
RaiNKhaN told PokerListings.com he liked what he saw.
"I'm impressed, because there are two difficulties in what he was trying to do," Khan said. "It's very hard to play 62 tables and turn a profit, and it's also very hard to play that many tables without starting smaller and working your way up."
Khan pointed to Grospellier's excellent command of sit-and-go strategy as the key to his success.
"I liked his play a lot," he said. "I thought he played tight, which is good in SNGs, and he knew when to shove, which is essential if you're going to turn a profit."
"It's really nice to have the record," Grospellier said. "I'm really happy I managed to succeed without adequate preparation.
As ElkY ground his way toward the record, Day 1a of the EPT Grand Final was playing out its eight sixty-minute levels.
A total of 396 players paid the €10,600 entry fee and by day's end about 230 players were left standing.
Action continues in Monaco with tomorrow's Day 1b, in which ElkY will look to continue his winning streak by facing off against the likes of Christina Milian, Nico Rosberg, Nelly and former champs Glen Chorny and Gavin Griffin.
Play kicks off at noon local time (6 a.m. EST). Check out all of the day's highlights in the PokerListings.com Live Tournaments section.