The difference between those two events? 12 months, of course, but not just any 12 months - 12 months of immense growth for the Namibian side.
"There was more hype and childish belief last year," Erasmus said. "This year was more something of [knowing] we can relate to that level. Mentally, we can relate to that level. We can also now physically and skilfully relate to that level."
After that heavy defeat in 2021, Namibia recovered to have a fairy-tale run through the group stages and qualified for the Super 12s. There, they beat fellow Associates Scotland but were blown away by bigger teams. They lost to Afghanistan, Pakistan and New Zealand by margins of 45 runs or more and to India by nine wickets, and lessons were learned.
"We've played India, Pakistan, all these teams before," Erasmus said. "We've seen it, we've tasted it and we've sort of closed that gap by becoming one step closer to them and getting the physical feel of what it's like. That gave us the belief this time around."
If at any point Namibia were flirting with a false sense of grandeur, they were brought right back down to earth when they saw, what Erasmus called, "the tabloids", which gave them "about an 11% chance" of beating Sri Lanka.
"As soon as we knew that, it gave us that underdog feeling again. Having that with a bit of real belief, not the childish, behind-the-scenes belief that you've played at that level - that's what happened today. We just went onto the field on an equal footing to the Sri Lankan side."
"The experiences we had from last year's World Cup really gave us a good idea of what type of skill we need to have to be able to compete at this high level. The speed of the ball is more, the quality of the skills and the percentage of execution that guys are playing at is higher"
It didn't always look that way though.
Namibia were 35 for 3 inside five overs and 93 for 6 in the 15th before showing some of the progress they have made. Jan Frylinck and JJ Smit took advantage of a Sri Lankan attack that went with slow, short deliveries at the death and gave Namibia what Erasmus thought was an above-par total.
"The experiences we had from last year's World Cup really gave us a good idea of what type of skill we need to have to be able to compete at this high level. The speed of the ball is more, the quality of the skills and the percentage of execution that guys are playing at is higher. We got some powerplay boundaries today which were scored behind square. We were much more comfortable playing mystery spin [Maheesh Theekshana] and [Wanindu] Hasaranga towards the middle and towards the latter end, bludgeoning the ball a bit harder. Those types of skills, we've had to put together over the last 12 months."
In this time, Namibia have had several opportunities to test themselves. They went toe-to-toe with Uganda and Zimbabwe. Playing as the Richelieu Eagles, they were also part of a domestic T20 tri-series that included the Lahore Qalandars and Lions from South Africa. Erasmus emerged from that competition as its third-highest run-scorer.
Over the last 12 months, Namibia focused on how to play the short ball, which is what they expected to be their biggest threat at this World Cup.
"We worked on synthetic wickets - AstroTurf and cement wickets - at home and we trained for the short ball since we know the bounce is a bit more in Australia," their batter Jan Nicol Loftie-Eaton said
Apart from attempting to mimic Australia as much as possible, they also roped in, as bowling consultant, an adopted Australian: Morne Morkel, the brother of their assistant coach Albie and someone who knows more about the short ball than most. While Zane Green described Morne as the yang to Albie's yin - "the fun guy that brings the energy to training and matches" - Erasmus said just having someone different has helped. "Being a team where there are not many fresh players coming in because of our small player base, it's always brilliant to have someone new on the coaching staff."
While facing Morkel in the nets would have helped improve the batters' skills, his primary job was to help the bowlers and the results are already showing. The Namibian quicks stuck to a hard length and an off-stump line to force a Sri Lankan collapse that will be talked about for ages.
Last year losing to Sri Lanka was the catalyst that pushed Namibia to up their game and reach the Super 12s; this year, beating them has to do the same job. It's only the first match of three and Namibia can ill afford to take their victory for granted, even though they are going to celebrate it for everything it is worth.
"Everyone is very glad at beating a Test nation for the first time ever [Namibia have previously beaten Ireland and Zimbabwe], and on a world stage, in the opening game," Erasmus said. "It's a massive event in our lives and it should be celebrated. But it's going to take a massive mental reset from our point of view because we can get carried away with celebrations and historic events like this. The recovery periods between these games are so quick. It's only the start of the tournament and we really need to have our eye on qualifying for the Super 12s, which is the main goal for me."