Garnacho climbed off the bench for the final ten minutes to net the insurance goal as the Red Devils enhanced their Champions League prospects with a 2-0 victory.
Garnacho was returning from a two-month injury layoff following an ankle issue sustained against Southampton back in March.
The 18-year-old has been one of the success stories in Manchester United's season, making 30 appearances across all competitions and scoring five goals while providing four assists.
Ten Hag was impressed with what he saw from Garnacho and wants more from the Argentina youth international.
“Garna, of course, scored a great goal,” the United boss said. “He came in, he did I think almost everything good and then he scored a goal.
“That will give him belief and that is good for us for the rest of the season that he is back. It’ll give him confidence and he can have an impact.
“He is showing when you score some winners, like Fulham, assist against City, for instance. Now the second goal, he is showing some things.
“Also sometimes he lacks defensive transition, in pressing, he has to step up in such things. Also, when you are going into an action or keep the ball, so decisions.
“But I think when you see it all over, yeah, he is a huge talent and he’s brave.”
“One of the aspects from the biggest talent is that they are mature,” Ten Hag added. “First, they take responsibility and, second, they are mature.
“To bring in their skills, they have belief that they can dominate opponents and I think once again he did it.
“He has a big impact in many games either when starting or coming on, he’s ready, straight into the game and that is so important for the squad you can bring such players.
“I am happy that you can bring young players and hopefully he will progress so quickly that he can compete for a starting XI position because that is his next challenge.”
Garnacho recently signed a new contract with United until the summer of 2028.
