Ahead of today's clash with Sunderland at Old Trafford, Amorim insists he's pleased with what he's seen from the summer signing.
Sesko struck his first goal for United in defeat at Brentford last week and Amorim told MUTV: "The most important thing is to win games.
"That will give confidence for everybody in the team.
"Of course, he was anxious for his first goal. The thing I like most in Ben is, even when things are hard for him with the ball, he is working hard in every minute of the game.
"That is the most important thing in the moment."
On today's clash, Amorim also said: "It's a massive difference to go to the stop with a positive result and we have to win it. So, again, we are in the beginning of the season, we could do better in the last games, but, we prove already when we are focused, we can win any game.
"It's really important to win this one to enjoy the break."