Goals either side of half-time from Martin Paterson and Charlie Austin were enough to hand the Clarets the three points.
Solbakken said: "It was a bad performance overall until there were 15 or 20 minutes left.
"When they scored the goal they were on top and I changed it around and at the end we had chances to score but it was one of those days.
"I must say that players who for a long time had been rock solid had off days and I probably picked the wrong team, although I was confident before the game that we would have a very good game and we didn't do that.
"All the players tried as hard as they could but they didn't have a good day and it is down to the manager.
"We have to make sure that this form drop does not last for long.
"We were unlucky in the last 20 minutes but we could be playing until now and still not score.
"It is important not to hide behind anything. It was a bad performance for long periods and it is as simple as that - we were not good enough.
"When we have to play the long game we get smashed and I think I have seen enough of that now. We don't have a powerhouse like (Charlie) Austin, we have different types of player."