The Australian described the Lions' display as "a great all-round performance" and insisted that his team are in with a chance of progressing to the final.
"Unbelievable. We're through to Wembley. We're just buzzing for the club and the fans," he told BBC Sport.
"I cleared one off the line that was going in, but that's why I'm thee. But it was a great all-round performance and to get through to Wembley, I'm just ecstatic.
"Danny Shittu managed to out-muscle his marker and score the goal. And in 90 minutes of football in the semi-final against Wigan, anything can happen."
Millwall manager Kenny Jackett also praised his side, claiming that they could have won the match by a higher scoreline.
"It is a great experience, I have even lost my voice slightly. The players played well," he said. "Scoring goals was a problem and I thought we should have scored more as the game was there for us to win by two or three goals."
Millwall will face Wigan in the semi-finals next month.