The Argentine winger scored the third goal in a comfortable 3-0 win over Leicester City on Sunday.
The Red Devils are still in 13th place in the table, but are only four points away from a top four spot as well.
On Garnacho not celebrating after scoring, the interim manager stated: "It doesn't really matter to me. I saw it going into the top corner and I'm glad it worked out. I spoke to him before the game and said he'd had a lot of games and a lot of minutes, so you need to make the difference from the bench. I'm glad it worked out.
“The team, as a whole, fought and did everything they could."
On the team’s trajectory under new boss Ruben Amorim, he added: "What we try to do is obviously try to stabilise, after a very difficult, emotional period.
“You want to get the players performing at their best, so a lot of communication and training sessions, to get the right feeling across to them. It's about believing in themselves and, look, the only way is up.
“It's where we want to go, as a club and as a team, to get results going and build on it."