United must first get the job done in Switzerland by avoiding defeat and Fletcher, who put Sir Alex's side ahead in the second half, is understandably keeping a cool head.
"We're disappointed as topping the group looks like it's going to be difficult now," he told MUTV. "It's still in our hands to go to Basel and get a positive result and go through.
"We've lost goals at bad times and they were bad goals, but these things happen. We lose goals as a team and we created enough chances to win the match by a few goals. Unfortunately we didn't take them and suffered because of that.
"The first [goal we conceded], Phil Jones couldn't do much about it. It was the same for Rio Ferdinand, who was in a good position defensively, but it just comes off him and falls to their lad [Pablo Aimar] nicely. We're disappointed in that respect but, like I've said, we created enough chances and played some good stuff.
"Benfica are a good side. We experienced that when we played them out there. They're having a good season in their domestic league so we were under no illusions that they were going to have a go and it was a decent match to play in.
"Obviously we need a bit of luck [to finish top of Group C], but I fully expect Benfica to go and win their match. We'll go to Basel to win our match with a faint hope of topping the group but the most important thing is to get into the next round, even though you want to win the group. If we play one of the top sides, so be it, we'll look forward to that challenge."