Burnley boss Scott Parker said his side were below par in their 0-0 draw away against Portsmouth.
Parker told BBC Radio Lancashire: "It's a difficult place to come as you can see from their results over the past few weeks.
"They are a different animal at home, an aggressive team who put you under pressure constantly with a real intent and we had to stand up to that.
"That's the one positive because this game could have looked a lot different if we didn't have that resilience about us.
"On the flip side, we weren't at our best.