"We were heavily criticized at that time but our decision to bring in Decastel proved fruitful," Amer, whose time in office nears an end, told a news conference on Sunday.
"Some people thought that we did not need a foreign manager but Zamalek board believed the football team needed to be rebuilt."
Decastel was named as the Cairo giants' boss in January in a bid to turn around their fortunes after a dismal run.
Zamalek, who faced the unthinkable prospect of being relegated to the second division earlier in the season, put in some fine displays under the Swiss tactician.
Decastel promoted several youngsters to the senior team as he sought to rely on fresh players.
The likes of Hazem Emam, Ahmed Al-Merghani and Sabri Rahil produced impressive performances to help Zamalek move into sixth place in the league table and ease their woes.
Neutral Board
Amer insisted that neither he nor the board members will support any presidential candidate in Zamalek's elections, which will take place on May 28th.
"We will be neutral, we don't have any preferences," he added.
Controversial lawyer and Zamalek's last elected president Mortada Mansour is expected to face a fierce battle against competitors to regain his presidency.
Wealthy businessman Mamdouh Abbas and Kamal Darwish, who enjoyed a highly successful spell at Zamalek's helm in the early 2000s, are expected to pose the greatest threat to Mansour.