McAllister said: "It's the first time Jermaine has gone through a barren spell since I've come here, but he's a confident boy and it was a superb hat-trick from him."
McAllister is looking forward to visiting Histon in the second round and is adamant that the FA Cup is not a distraction to Leeds' promotion hopes.
"He added: "It's a competition I'm fond of and we want to progress and do as well as we can in it.
"The game at Histon is a classic FA Cup tie, but we'll be giving them every respect and I'll be going to watch them before we play them."
Meanwhile Stuart Gray has to rally his troops ready for the weekend's league action at Hereford.
He watched in disbelief as his side crashed out of the Cup.
"It was a freakish game. Individual errors have cost us but we're all in it together," said Gray.
"There were too many errors, poor defending and we gifted them goals. The first 20 minutes we were punished for every mistake we made and at the other end we've had chances but their keeper's made a couple of decent saves.
"I still thought if we could cut out the mistakes in the second half we could have salvaged some pride. The main problem is we've got four or five strong characters out injured but it's up to the players out there to roll up their sleeves and get on with it."