Winger Nani was the star for his country on Friday night as he scored twice in Portugal's 3-1 win over Denmark when carrying his club form to international level.
Ferguson has been impressed and wants the 23-year-old to continue to shine as United attempt to compensate for the loss of Valencia, who broke his leg in the Champions League against Rangers in September.
The United boss told the Manchester Evening News: "It's a loss to lose any player but Antonio was probably the most improved squad member over the last 12 months, so it was a big blow.
"The development we saw from when he signed for us to the present day has been amazing. We thought it would take a couple of years for him to reach this level, but he took to the challenge like a duck to water.
"However, we've got a strong squad and we'll cope. It's up to Nani now to play his part, and he has done superbly this season, so he'll offer us width.
"Then there's also Gabriel Obertan and the boy Bebe, who's training very well. We're not too bad - we've got options."