The point extends the Robins' run without defeat to 21 games and leaves them five points clear at the top of the table.
"Everyone wants to beat us; that's pressure, but we showed composure to come back and get a point," Cotterill told reporters.
"It was a really good game, end-to-end. Their crowd got them going. It's a very tough place to come.
"You always want your strikers to score so I'm delighted Aaron Wilbraham managed to get the equaliser."
Bristol City return to action next Saturday when they welcome Oldham Athletic to Ashton Gate.