The Bees were beaten 3-0 at home.
Mee said, "We never got going.
"It's difficult to put your finger on it. It's the first time that has happened to us this season. They kept the ball well and came back at us. It's tough.
"They were motivated to come here and get one back on us after last season. There are always things we can work on. We will see what we can do better.
"It's been a positive start to season and we will build on it."