England moved to 326 for six on day three at Trent Bridge - a lead of 261 - and Pietersen told Sky Sports: "We've got some incredible bowlers and I think we're licking our lips at the position we've got ourselves into.
"It's fascinating stuff. It's calm in the dressing room but there's a tenseness because we are only 261 ahead.
"We've got ourselves into a very good position in this Test."
The South African-born batsman, who made 64 before being bowled off an inside edge, said of the dismissal: "The pace wasn't in the wicket for me to hit that ball for four.
"It's a cruel game sometimes but you take the rough with the smooth."