United lost 2-1 at Old Trafford and also surrendered their Premiership leadership.
Vidic said: "We are disappointed.
"When you see their second goal I am disappointed even more.
"We played much better in the second half than the first. We created some good positions but our final ball could have been better.
"We were more creative in the second half. We played a bit higher and had more opportunities.
"If our final ball had been better maybe we could have been celebrating."