In front of his home crowd as rain pelted down at the new Southport acquatic complex, the 20-year-old McEvoy upstaged the heavyweight duo of Olympic gold medalist Nathan Adrian (USA) and world champion James Magnussen to announce his arrival in one of the sport's blue-ribbon events.

Even the return of the great Michael Phelps, who finished fourth in a hugely encouraging result for the American icon, couldn't stop the run of McEvoy, who put the writing on the wall with a strong heat swim and stepped it up a gear in the final, demolishing a brilliant field with a Pan Pacs record swim of 47.82.

Adrian was the fastest qualifier in an event that he and Magnussen have dominated for the past three years. But with McEvoy's swim in the final, it was clear there was another major threat on the horizon as the swimmers look toward next year's world titles and Rio in 2016.

"It's definitely not a two-man game anymore," said Adrian, who swam a 48.3 for silver. "It's silly to think it's just going to be James and I winning all the time."

Magnussen said it would take a sub-48 second swim to win the gold and he was right. But it wasn't him who would deliver as team-mate McEvoy took a massive leap forward against the best swimmers in the business.

McEvoy said he was relaxed - just happy to be there - and seemed stunned with the result of what he described as an almost 'perfect' swim.

"To me, it felt pretty perfect. I was just happy to be there with such great company in that race. I just wanted to enoy it. When's the next time I'm going to be in a race with people like that? That's how I approached it," McEvoy said.

"You do always have to have in the back of your mind that there is the possibility of you winning. In saying that, I wouldn't have been disappointed if I didn't win. I guess I was thinking about it a little bit but I just wanted to focus on being there and enjoying that in itself."

Magnussen had been struggling with a back injury all meet yet hit the wall hard in his heat swim. But when McEvoy put his foot down in the final 50m, the Olympic silver medalist couldn't match motors and was left in the wake of his relay team-mate.

He said he had tried to keep his back injury under wraps all week but later revealed he had been in hospital as recently as last week to try and get some relief from the pain.

"I just didn't quite have the preparation to go fast tonight," Magnussen said. "This time a week ago I had all but ruled myself out, I was in hospital getting an epidural and a couple of cortisones so I wasn't in a good way. I thought they only gave epidurals to ladies having babies so I was really worried when they gave me that one."

Earlier, women's sprint queen Cate Campbell added Pan Pacs gold to her world and Commonwealth titles, blowing away the field in the women's 100m freestyle to continue her domination of the event.

She qualified nearly a second faster than her sister Bronte, who held on for silver, and delivered again in the final to record a 52.72, with Bronte swimming a 53.45. Now she wants to add Olympic gold to complete the set.

"It was stinging a little bit but I'm happy to come away with a win. This meet is notabout racing for times its racing for places because everyone is in a world of pain at the moment," Campbell said.

"Absolutely I'm so excited (for Rio), I almost don't want to have a break. We've got two years to go and it's looking very good."