Rashford, 25, headed in his 21st goal this term in Sunday’s 2-0 win at Leeds.
“I don’t know when it will stop but if you are satisfied with it, then it will,” said Ten Hag.
“And because satisfaction goes to laziness, you have to keep investing every day. When he keeps the investment and keeps the focus in every game and brings the energy and belief in, he will keep scoring.
“He has the skills to score with right, with left and with his head. It’s about him getting into position.”
England international Rashford now has 114 United career goals to sit 19th on the club’s all-time list.
And since the World Cup in particular, he has been in a rich vein of form, scoring 13 goals in 15 games. Rashford has only failed to find the net in three of those matches. Ten of them have ended in victory. Only one – at Arsenal – brought a defeat.
Little wonder Ten Hag said Rashford is “definitely one of them”, when asked if the forward is the best in Europe at present.
Rashford endured a disappointing 2021-22 season, when he scored only five times in all competitions and just twice in his last 28 games of an injury-hit campaign.
Even this season, Rashford only scored five in his first 13 appearances before finding the net in successive matches at the end of October.
Ten Hag said he fully believed he could improve Rashford when he took charge at United last May.
“I was convinced from the first moment,” said Ten Hag. “I was really excited to work with him. I thought I could get more out of him.
“He has so many skills and such high potential and there can be even more.”