United had their most disappointing Premier League season in 2024/25, finishing 15th in the league table, and also missed out on Champions League qualification after losing the Europa League final 1-0 to Tottenham Hotspur.
The Old Trafford team did not perform well in the 0-0 draw against newly promoted Leeds in Stockholm on Saturday, despite the presence of new signing Matheus Cunha in the starting eleven.
"We struggled a bit when we attempted to press high; they cleared the ball, won the second ball, and posed a threat during that time," Amorim told MUTV.
"We are lacking speed, particularly in the midfield, and it's noticeable, which makes it difficult to advance the ball. However, we created opportunities. We have much to improve, but it was a first test against a Premier League side, with two different teams, so it was a valuable test...
"As a team, we have many areas to enhance, including the pace of play and all the finer points, so, yes, we will improve."
United will next face West Ham United at the MetLife Stadium in New Jersey on July 26th.