Some have questioned McTominay's pedigree since he broke through the academy ranks under Jose Mourinho.
But Solskjaer has shown faith in him, with the Scotland international scoring United's 2000th Premier League goal in the 3-1 win over Norwich City on Sunday.
"Scott McTominay knows that it is a mistake but still a very good performance," said Solskjaer.
"He is growing all the time, the kid and he is a top professional. He works hard very day and is a Manchester United player.
He added: "This had been a good week for us. It started with a decent performance against Liverpool and now two wins away from home. It gives the players confidence and momentum."