The international colleagues will come face to face when Liverpool travel to Old Trafford in the Premier League this weekend.
McTominay has started all eight league games of a disappointing campaign for United, who are down in 12th place after winning just two of those matches.
Despite his club's on-pitch struggles, the 22-year-old has been hailed as a shining light by compatriot Robertson.
"He's been excellent all season in a United team that has had its critics. I think he's carried himself very well," Robertson said, quoted in several British newspapers.
"I'll be looking forward to facing him on Sunday. Obviously, I hope to come out on top."
While United have struggled in Ole Gunnar Solskjaer's first full campaign, bitter rivals Liverpool are flying at the top of the table after making a perfect start.
However, the Reds are winless in their last five away league meetings with United - something Robertson is keen to put right.
"I think what makes the fixture so special is that it's historic," he said. "There have been such great battles down the years.
"And they've always had top teams who have always fought against each other for everything on the pitch.
"It's always like that. And it's genuinely a different atmosphere when you play against them. It's one game that we always look forward to.
"Since I've been a Liverpool player, we've not managed to get a result at Old Trafford. So hopefully that changes on Sunday."
Manchester United will be without both Paul Pogba and David De Gea after Solskjaer confirmed the duo had not recovered from injuries.
However, there is a chance that Anthony Martial, Luke Shaw and Aaron Wan-Bissaka could return to the squad having been absent prior to the international break.
Liverpool star Mohamed Salah has been under an injury cloud after a tackle from Leicester City's Hamza Chodhury left him limping in the Reds' last Premier League match.
But the Egyptian used the international break to recover from the knock and is expected to available for selection.