The 21-year-old swam 47.56 seconds on Friday night to become the third fastest man in the blue riband event since textile suits were banned in 2010 and establish himself as a contender for Olympic glory in Rio de Janeiro later this year.
Only Magnussen, who clocked his personal best of 47.10 in early 2012, and American Nathan Adrian, who swam 47.52 to win gold at the Olympics that year, have gone faster without a suit.
Brazil's Cesar Cielo still holds the world record for the event with the 46.91 in a textile suit in Rome in 2009.
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"Everyone in the world has already stepped up and I had to step up in my own way, I fully expect everyone to be reading the results tonight and it will fire them up to get back in the water," McEvoy told reporters.
"To come out and swim a best time when I’m not fully tapered at all, that’s exciting. On a personal note, it is kind of cool to be amongst names like James Magnussen and Nathan Adrian on the rankings too."
Former world champion Magnussen, who lost out to Adrian by a fingertip at the London Olympics, is returning from shoulder surgery but was still disappointed with his time of 49.34.
"This is a starting point now and I will only get faster from here", the Australian said.
"I know my fitness is good because I am not fading. I just need to get that top end speed up.
"I can't really help what Cam is doing at the moment. I am trying to come back from an injury so I can only really focus on myself at the moment."
McEvoy finished second behind China's Ning Zetao at the world championships in Kazan last year.
Australia last had a men's Olympic champion in the blue riband event when Mike Wenden won gold in Mexico in 1968.
(Reporting by Nick Mulvenney, editing by Peter Rutherford)
