This week he will be named in Craig Levein's squad for the crunch Euro 2012 double-header with the Czech Republic and world champions Spain.
Scotland currently top Group I and Ferguson sees no reason why Levein's side can't stay in pole position.
And he hopes Fletcher - who won his 50th cap against Liechtenstein in the last qualifier - can inspire the side to two massive results.
The United gaffer told the Sunday Mail: "Darren played well for Scotland against Liechtenstein.
"He is a very even-tempered boy, rarely up or down. Any criticism that comes his way doesn't bother him. He's not what you call a graceful player. He's 6ft 1in and gangly.
"But you ask any player in England to name one of their toughest opponents and Darren would be mentioned.
"He has great energy and closes players down quickly. He also has great movement off the ball. Darren gets close to people quickly and sticks out his long legs to rob them of the ball. He's brilliant at it.
"Darren never misses a big game for us. He is highly-rated here.
"He maybe feels a burden when he's with Scotland because he's not playing with the same type of players."