While Leeds were awarded two penalties during the Elland Road tie, with Stephen Warnock securing the win with his second-half spot kick, Jackett argued that referee Mike Jones made the wrong decision when Sam Byram looked to have handled the ball.
He said: "My first impressions are that we couldn't complain about either of Leeds' penalties but I felt we had a clear-cut penalty when Danny Shittu headed the ball down, Sam Byram had his hand by the side of his body and clearly handled it as the ball was going through to my centre-forward.
"I thought the referee got that call wrong.
"David Forde made a good save from the first penalty and he is in top form at present. We had big chances but Paddy Kenny pulled off two very good saves for them and Shane Lowry hooked one over from about seven yards, so we were unfortunate to come away with nothing."