Adil Rashid backs England to bounce back from shock Afghanistan loss
Afghanistan posted 284 after half-centuries from Rahmanullah Gurbaz and Ikram Alikhil, before bowling out England for 215 to claim just their second victory at a World Cup.
It was England's second defeat of the tournament, after they were beaten by nine wickets in their opening game against New Zealand earlier this month.
"It's part and parcel of the game. We're not too concerned, it's just a game that we've lost," Rashid told reporters. "We know we've got tough competition coming up, but I'm confident we can play really well as a unit moving forward.
"We know we've still got six games, hopefully we can win and get some good momentum going forward. I'm quite confident in the squad. I'm sure we'll bounce back strong.
"You are going to have games where players are out of form but I do believe we've got the squad, we've got the team and we've got the mentality to still be hungry."
England, who face South Africa in Mumbai on Saturday, are fifth in the standings with one win from three matches. The top four teams from the group stage advance to the semi-finals.