Having never made it past the round of 16 at the season-opening major, 11th-seeded Ruud impressed on Tuesday in a 6-1 6-3 6-1 win over Spain's Albert Ramos-Vinolas on Margaret Court Arena.
The three-times grand slam finalist took just over two hours to dispatch the former world No.17 as the temperature soared past 30C.
Ruud comes into the Open in hot form, winning all three of his singles matches for Norway at the United Cup.
But the 2022 and 2023 French Open and 2022 US Open runner-up's past performances at Melbourne Park remain a black mark on his record.
Ruud's best result came in 2021 when he retired in the fourth round against Russian Andrey Rublev with an abdominal injury and he was stunned last year in the second round by American Jenson Brooksby.
The 26-year-old Oslo native acknowledged he was yet to make a deep run at the Open but said a few pre-season tweaks, including changing his physiotherapist, had him primed to change that.
"It's been a couple of years in a row where I wasn't able to play as well as I hoped down here," he said.
"So hopefully 2024 we can turn that around."
Rudd will face Australian world No.45 Max Purcell next up after he held off Hungarian qualifier Mate Valkusz 3-6 7-6 (7-2) 6-4 7-5.
"He's a tricky player. Obviously I lost to him in Cincinnati," Rudd said.
"You wouldn't think it, but he has a really good serve."
Rudd remains on course for a third-round clash with in-form Brit Cameron Norrie, who smashed 30 winners past Peru's Juan Pablo Varillas on his way to a 6-4 6-4 6-2 victory on Tuesday.
Norrie is the only British man or woman to be seeded at this year's Open and has the distinction of being the only player this summer yet to beat Australian star Alex de Minaur.
World No.8 Rune, who has also never been past the fourth-round at Melbourne Park, was made to work in his 6-2 4-7-6 (7-3) 6-4 win over Japan's Yoshihito Nishioka.
The Dane hit a whopping 71 winners during the centre-court clash on Rod Laver Arena, advancing to the second round at his fifth slam in six starts and tallying his 99th career win.
French wildcard Arthur Cazaux awaits Rune in the next round after he won a five-set thriller over Serbian world No.33 Serbian Laslo Djere.
Elsewhere, Bulgarian 13th seed Grigor Dimitrov battled back to down Hungarian Marton Fucsovics 4-6 6-3 7-6 (7-1) 6-2, Adelaide International winner Jiri Lehecka eased past Spain's Bernabe Zapata Miralles 6-3 6-2 6-3 and American 14th seed Tommy Paul defeated France's Gregoire Barrere 6-2 6-3 6-3.
Sumit Nagal, meanwhile, became the first Indian man to beat a seeded player at slam since 1989 by ousting Alexander Bublik 6-4 6-2 7-6 (7-5).
Bublik joins Chile's Nicolas Jarry as the only men's seeds to bow out of the Open, with 28 booking their spot in the round of 64.
Since 2001 Wimbledon when slam draws went to 32 seeds, no more than 29 men's seeds have progressed to the second round of a major.
The high-water mark has been recorded on five occasions: at the US Open in 2001 and 2015, and the Australian Open in 2005, 2009 and 2014.
Later on Tuesday, world No.2 and two-time major winner Carlos Alcaraz gets his Open campaign under way against French stalwart Richard Gasquet.
German sixth seed Alexander Zverev faces countryman Dominik Koepfer despite the former being set to stand trial in May for allegedly assaulting a woman during an argument in Berlin, an accusation he denies.
