Basham has been one of the few United players to emerge with any credit from their games against Aston Villa, Newcastle United and Manchester United. That run of three games has seen Chris Wilder's pick up just one point, and concede six goals.
Despite their poor form, though, United are still mathematically in the race for Europe - and can also qualify via the FA Cup, if they can overcome their first hurdle on Sunday.
"We are going to be hurting a lot," said Basham.
"We have got a quarter-final in the cup on Sunday and we need to put things right and get that spark back which we had three or four months ago.
"We didn't lay a glove on Manchester United and are very disappointed with our own performance.
"We are disappointed with the way we have let the manager and staff down.
"We lost a bit of belief and didn't do ourselves justice or show up. We weren't ourselves. They showed their quality, we didn't show ours and that's why they won 3-0 and we didn't."
Basham was the only member of United's regular back three to feature at Old Trafford, with Jack O'Connell injured and John Egan suspended after being sent off at Newcastle. Dean Henderson was also missing, but Egan and Henderson will face the Gunners while Wilder hopes to have O'Connell available also.