The Reds defender told United Review: "We should have killed the game off early on but we took our foot off the pedal and let Fulham back into the game.
"But it’s always about your next game in football; you can’t dwell on the past."
Despite making an improvement on last season's opening two games and on the last two visits at Craven Cottage, the Reds already trail the league leaders by two points. But Evans says there's no need to worry about anything other than beating the Hammers.
"Last season you’ll remember we lost at Burnley in our second game, and we still ran Chelsea very close for the league," Evans continued.
"Obviously we want to win every game but it’s when you get late in the season that the games become really important. It’s still early days."
Read the full interview in United Review, the official matchday programme.