North End were beaten in last season's play-off semi-finals but already look capable of competing strongly for promotion again this term.
Saturday's goalless draw at home to West Brom has left Irvine's men in fifth spot going into the international break.
The Deepdale boss declared: "We have got 19 points so far, we are in a good position in the league and I think anybody who wondered whether there would be a hangover from missing out in the play-offs has got their answer.
"But we don't rest on that now, we have got a lot of work to do.
"We've got a lot of really tough games coming up and we want to make sure we are in contention come the end of the season."