The charismatic Ellenberger has had a field day with the stone-faced MacDonald, using social media and chats with reporters to poke fun at his opponent.
"He has been invented by the media and sold to the fans like a new Justin Bieber song," Ellenberger offered in the buildup to their televised UFC fight at the KeyArena.
"This is not a Tears For Fears lookalike contest," Ellenberger told a media conference call.
"Rory: Welcome to "Chez' Ellenberger". Tonight's special is CANVAS SANDWICHES served FACE DOWN. Bon' appetit,'" read one memorable Ellenberger tweet.
"Rory MacDonald: somebody who's been broken more times than the weekend curfew at the dorms at Vassar," read another tweet.
"McDummy. Bad News: Fighting Me. Good News: Handicapped Parking," read another.
"Which round is Rory getting melted? #YouChoose #UFConFox8," Ellenberger said, upping the ante.
That got MacDonald's attention, promoting him to fire back on Twitter: "4some1 with such a week jaw u sure use it alot 2 talk shit when ur done buildin ur self up ill b there 2send u back 2reality."
"McDummy," Ellenberger tweeted back. "Unless you are using a unit of time as an adjective, the word is "weak", not "week", Stupid."
The fact MacDonald broke down and responded was exactly the reaction Ellenberger was after.
"Every quick decision, especially in social media, is based emotionally," said Ellenberger. "I think it's funny, I do it for laughs. And he reacted the way I assumed he would. For me, I don't take anything personally. Anybody can say anything about me. And what they think about me, I could care less."
MacDonald, a native of Kelowna., B.C., who now trains out of Montreal, says he has no regrets about jumping into the fray. "It's fun to give your opinion back. It gets people excited for the fight."
We'll see Saturday night who has the last laugh.
Ellenberger is likely to want to get up close and personal with the Canadian, to negate MacDonald's reach and to bring his own power and wrestling skills to bear. The taller MacDonald is good at all aspects of the game, able to control distance, and is icy cold in the cage.
The fight has implications in the 170-pound division currently ruled by Georges St-Pierre, who shares a gym with MacDonald in Montreal.
MacDonald is currently ranked third among welterweights with Ellenberger fourth. GSP meets the No. 1 contender, Johny Hendricks, in November. And No. 2 Carlos Condit faces No. 7 Martin Kampman on Aug. 28.
By the end of the year, the pecking order among 170-pounders should be clearer.
MacDonald, who turned 24 on Monday, is 5-1 in the UFC and has won four straight. His last outing was also in Seattle, a dominant win over former lightweight and welterweight champion B.J. Penn. Prior to that, he had his way with Che Mills, Mike Pyle and Nate Diaz.
The young Canadian is seen as one of the new breed of MMA fighters. He took up the hybrid sport at 14 rather than coming to it from wrestling or kick-boxing. He had his first pro fight at 16, with his parents having to give their approval to do so. Even then, only a few athletic commissions would sanction the youngster.
Ellenberger (29-6) is a former collegiate wrestler and U.S. marine who is 8-2 in the UFC. The 28-year-old has real power in his hands and gets better each fight.
"If I'm on, I can beat anyone in the world," he said Wednesday after a public workout.
"Everybody gives this kid too much respect," Ellenberger said of MacDonald. "He's got to fight me. That's the equation. He's got to deal with what I've got to bring. I have new things I can't wait to show."
He has already shown a fine ability to sell a fight, helped in part by MacDonald's serious demeanour. Around fight time, the Canadian is in full-on funeral mode.
Ellenberger was all smiles Wednesday, explaining that he had upped his Twitter game for this fight just to have some fun and entertain the fans. The strategy seems to be working.
The co-main event of MacDonald-Ellenberger has been overshadowing the main event in which local favourite Demetrious (Mighty Mouse) Johnson defends his flyweight (125-pound) title against John Moraga.
Still Ellenberger acknowledges talk is cheap.
"At the end of the day, it doesn't matter if you say something or not," he said. "Either way I'm focused on the fight."
And MacDonald knows the talk will be over this weekend, saying: "We'll see Saturday night."