The Spaniard has received criticism from a number of pundits for some of his performances this season, including from former United defender Gary Neville.
However, having produced a string of saves during yesterday's 1-0 win at Fulham, Evans stated his belief that the 22-year-old keeper is underestimated.
"He made some outstanding saves, especially the one from Ruiz, which he tipped onto the post," Evans told the club's official website. "We're used to seeing that from him.
"We didn't necessarily think, 'great save', because we're used to him doing that. I think people underestimate his shot-stopping ability."
De Gea joined United in 2011 from Atletico Madrid.