Rashford had been dropped to the bench for the Premier League match at Wolves.
The striker came off the bench to inspire United’s 1-0 victory at Molineux having been sanctioned for breaking manager Erik ten Hag’s rules.
It lifted United into the top four and above Tottenham – who host Aston Villa on New Year’s Day – and Rashford admitted he was to blame for being axed.
He told BT Sport: “Obviously it’s team rules. I made a mistake. That can happen. I’m obviously disappointed not to play but I understand the decision and I’m happy we managed to win anyway.
“We draw a line under it and move on. I was a little bit late for a meeting. I overslept but it can happen.”
Ten Hag added: “Everyone has to match the standards and rules. We have to have consequences and it is what I expect on the pitch. He gave the right answer.
“I was not satisfied with the performance in the first half. We have to be more clinical and we know Rashy can score the goals and that’s what he did.
“We are a team, it’s hard to beat and that’s because we are attacking with 11 and defending with 11. When you are out of the pitch and missing the standards and rules it also flows onto the pitch.”
Casemiro’s header deflected over before Alejandro Garnacho wasted United’s best chance of the first half when he failed to beat Jose Sa after latching onto Nelson Semedo’s awful backpass.
Wolves were competitive but United still found openings, with Antony heading at Sa.
Rashford was summoned from the bench at the break but it was Wolves who threatened first when David De Gea tipped Ruben Neves’ brilliant free-kick wide.
Yet there would be no stopping Rashford scoring the winner with 14 minutes left when he swapped passes with Bruno Fernandes, held off Jonny and Nathan Collins and beat Sa.
Only a VAR call for handball denied him a second a few minutes later, after the ball hit his arm when Sa saved his initial effort.
De Gea still needed to keep out Raul Jimenez’s stoppage-time header and Wolves will end the year in the relegation zone.