The Red Devils had to cope with a major reshuffle when Ander Herrera, Juan Mata and Jesse Lingard were all forced off during the first half.
Striker Marcus Rashford also picked up an injury early on but was forced to play the rest of the match as United had no substitutions left.
However, Ole Gunnar Solskjaer's side rose above that adversity to earn a credible point and become the first side to stop Liverpool scoring away from home in the Premier League this season.
Speaking to reporters after the game McTominay praised the resilience of his teammates and highlighted the impact of the supporters, who created a rousing atmosphere inside Old Trafford.
“Of course it’s never easy losing three players in the first half. It’s an absolute credit to the boys for handling a game of this magnitude so, so well,” said the midfielder, who himself only started because Nemanja Matic suffered a muscle injury in training.
“As soon as the boss asks you to be ready you have to be ready. You want to play for the boys and hopefully I did that as well as I could today.
“Last year was a great experience to win that game [2-1 vs Liverpool], this year we fell short. It’s always frantic in the middle of the pitch. It was a bit of a disruptive match.
“It’s not easy [losing three players in the first half], never mind one player getting taken off in the first half. We’ve got boys on the bench, myself, Andreas [Perrera] and Fred who are dying to get minutes.
“The fans were immense today, I’ve never played in an atmosphere like that today.
“It’s United fans thick and thin. You’re a Manchester United player and they are that 12th man."
Teammate Luke Shaw also praised the home fans for their backing and felt United could have taken all three points despite their injury setbacks.
“The crowd was unbelievable and as players we appreciate the support. Hopefully they continue that and next time we’ll give them a better result,” said the full-back.
“For me, I think it’s two points dropped. Of course, they are a brilliant team and we deserved to win today with the chances we created. We created much more than them. It’s a good point but we’re disappointed we didn’t get all three.”